🌤 Weather at Patapsco Valley State Park by season
| Spring | Summer | Fall | Winter |
|---|---|---|---|
| 34–73 °F | 64–86 °F | 39–77 °F | 27–46 °F |
Each range runs from the coldest monthly average low to the warmest monthly average high in that season (1991-2020 climate normals), measured at Cylburn, 8 mi away, elevation 235 ft. Conditions at the park can differ from the station, especially where elevation differs — check a forecast before you go.
🌲 Patapsco Valley State Park – The Complete Guide – Updated 2025
Maryland’s Crown Jewel of Outdoor Recreation
🏅 Official Guide: Patapsco Valley State Park — One of the oldest and most popular state parks in Maryland, spanning over 16,000 acres along 32 miles of the Patapsco River between Baltimore and Washington, D.C.
Stretching through five distinct recreational areas across Baltimore, Howard, Carroll, and Anne Arundel counties, Patapsco Valley State Park is the outdoor playground for the entire Baltimore-Washington metropolitan area. With over 200 miles of trails, historic mill ruins, thundering waterfalls, and one of the most impressive historic railroad bridges in America, this park delivers an experience that rivals destinations many times its fame.
The Five Areas of Patapsco Valley
Unlike most state parks that operate as a single unit, Patapsco is divided into five geographically distinct areas, each with its own character, entrance, and fee structure:
| Area | Character | Top Features | Best For |
|---|---|---|---|
| Avalon / Glen Artney | Most popular, well-developed | Cascade Falls, Swinging Bridge, Thomas Viaduct viewpoint | Hiking, picnicking, family outings |
| Orange Grove | Scenic, riverside | River access, Bloede Dam ruins, historic mill sites | Fishing, nature walks, photography |
| Hilton | Wooded, quieter | Hilton Area trails, shelters, playground | Group picnics, short hikes, family BBQs |
| Hollofield | Rugged, forested | Mountain biking trails, backcountry feel | Mountain biking, trail running, solitude |
| McKeldin | Remote, expansive | Rapids overlook, Switchback Trail, river tubing | Whitewater viewing, trail running, fishing |
Top Trails
| Trail | Distance | Difficulty | Highlights |
|---|---|---|---|
| Cascade Falls Trail | 0.3 miles one-way | Easy | Stunning 15-foot waterfall, rocky gorge setting. Most popular trail in the park. |
| Valley View / Ridge Trail Loop | 4.5 miles | Moderate | Panoramic river valley views, dense hardwood forest |
| Grist Mill Trail | 3.8 miles | Easy–Moderate | Flat riverside path past historic mill ruins |
| Switchback Trail (McKeldin) | 5.2 miles | Moderate–Difficult | Varied terrain with rocky outcrops and river overlooks |
| Morning Choice Trail | 7.0 miles | Difficult | Premier mountain biking trail with technical rock gardens |
| Buzzards Rock Trail | 2.5 miles | Moderate | Rocky ridgeline with views of the river valley below |
| Ole Ranger Trail | 2.0 miles | Easy | Gentle wooded walk, good for beginners and families |
Cascade Falls
The park’s crown jewel is Cascade Falls, a beautiful 15-foot waterfall tucked into a rocky gorge in the Avalon area. The trail to the falls is short and relatively easy, making it accessible for families with children. During spring runoff, the falls surge with impressive force; in summer, the rocky pool below becomes a popular wading spot (though swimming is officially prohibited).
To reach Cascade Falls, park at the Avalon area parking lot and follow the well-marked trail for approximately 0.3 miles. The trail crosses a historic swinging bridge suspended over the river, which is an attraction in itself.
Thomas Viaduct: A National Historic Landmark
Towering over the Patapsco River near the Relay area, the Thomas Viaduct is a stunning eight-arch stone railroad bridge completed in 1835. It is the oldest curved, stone-masonry railroad bridge in the world still in regular use, carrying CSX freight and Amtrak passenger trains daily. Designated a National Historic Landmark, the viaduct is best viewed from the Avalon area trails or from the river level below. At 612 feet long and 60 feet high, it is a remarkable feat of 19th-century engineering and a dramatic backdrop for photography.
Historic Mill Ruins
The Patapsco Valley was once the industrial heartland of early Maryland, powered by the river’s flow. Throughout the park, visitors can discover the atmospheric ruins of historic mills, including:
- Orange Grove Flour Mill — One of the largest flour mills in Baltimore County, now a haunting stone foundation along the river
- Avalon Iron Works — Remnants of a pre-Civil War iron furnace complex
- Daniels Mill Town — The ghostly remains of an entire company town, including foundations, retaining walls, and the old mill race
- Bloede Dam — Americas first underwater hydroelectric dam (1907), recently removed in 2019 for ecological restoration
Flooding History & Resilience
The Patapsco Valley has been shaped by catastrophic floods throughout its history, and understanding this context adds depth to any visit:
| Event | Year | Impact |
|---|---|---|
| Tropical Storm Agnes | 1972 | Devastating flood that destroyed the entire town of Daniels and severely damaged park infrastructure |
| Ellicott City Flash Flood | 2016 | 6+ inches of rain in 2 hours; two fatalities; massive erosion along the river corridor |
| Ellicott City Flash Flood | 2018 | Second catastrophic flood in two years; triggered major flood mitigation projects |
The park has demonstrated remarkable resilience, with trails and facilities rebuilt after each disaster. Some flood-damaged areas have been intentionally left as educational sites showing the raw power of water.
Mountain Biking
Patapsco Valley is one of the premier mountain biking destinations in the Mid-Atlantic region, with a trail network spanning over 200 miles across all five areas. The trails range from smooth, crushed-gravel paths perfect for beginners to gnarly, root-strewn singletrack with rock gardens that challenge expert riders.
| Trail | Level | Surface | Notes |
|---|---|---|---|
| Morning Choice | Expert | Technical singletrack | Rocky sections, fast descents, race-quality |
| Ridge Trail | Intermediate | Dirt/rock singletrack | Ridgeline views, moderate climbs |
| Grist Mill Trail | Beginner | Gravel/dirt | Flat riverside path, family-friendly |
| Hollofield Singletrack | Intermediate–Expert | Natural surface | Less crowded area, rewarding loops |
Fees & Passes
| Pass Type | Maryland Resident | Non-Resident | Notes |
|---|---|---|---|
| Weekday (non-summer) | Free | Free | October through April, weekdays only |
| Weekend / Summer Day Use | $3/vehicle | $5/vehicle | May through September, all weekends year-round |
| Annual Pass (Individual Park) | $40 | $50 | Unlimited access to Patapsco Valley |
| Maryland State Parks Pass | $75 | $100 | All Maryland state parks, year-round |
Dog-Friendly Policies
Patapsco Valley is a popular destination for dog owners. Dogs are welcome throughout the park on a leash no longer than 6 feet. The park offers several particularly dog-friendly trails with river access for wading. The Grist Mill Trail and portions of the Avalon trails are especially popular with dog walkers. Note that dogs are not permitted in the campground area or on the Cascade Falls trail due to the narrow, rocky terrain.
Camping
The Hollofield area offers the park’s only camping facilities, with 73 campsites (electric and non-electric) nestled in the river valley forest. The campground is usually open from April through mid-November.
| Site Type | Price/Night | Features |
|---|---|---|
| Standard (non-electric) | $21–27 | Tent pad, fire ring, picnic table |
| Electric | $27–33 | 30-amp hookup, fire ring, picnic table |
| Mini Cabin | $50–70 | Sleeps 4, bunks, no plumbing |
Getting There
| Feature | Details |
|---|---|
| Location | 8020 Baltimore National Pike, Ellicott City, MD 21043 |
| Coordinates | 39.2529° N, 76.7729° W |
| Size | 16,043 acres across 32 miles of river valley |
| From Baltimore | ~20 minutes (Avalon area via I-95 South) |
| From Washington, D.C. | ~45 minutes (McKeldin area via I-70 West) |
| Hours | Sunrise to sunset daily |
| Phone | (410) 461-5005 |
Frequently Asked Questions
Is Patapsco Valley State Park free?
It depends. Weekday visits from October through April are free for all visitors. During summer months (May–September) and all weekends year-round, a per-vehicle day-use fee applies ($3 Maryland residents, $5 non-residents).
Can I swim in the Patapsco River?
Swimming in the river is officially prohibited due to unpredictable currents, submerged rocks, and water quality concerns, especially after rain events. However, wading in shallow areas is generally tolerated at the visitor’s own risk.
Which area should I visit first?
For first-time visitors, the Avalon area is the best starting point. It offers the most iconic features (Cascade Falls, Swinging Bridge, Thomas Viaduct viewpoint) and the most developed trail network in a relatively compact area.
Are there restrooms in the park?
Yes. Restroom facilities are available at the main developed areas (Avalon, Hilton, McKeldin, and the campground). Portable restrooms are placed at some trailheads during peak season.
Nearby state parks: If you have extra time, Morgan Run Natural Environment Area is a short drive away, and Matthew Henson State Park is a short drive away.
🌲 Ready to explore Maryland’s river valley?
Plan your visit to Patapsco Valley State Park — 16,000 acres of trails, waterfalls, and history.
Explore More Maryland State Parks
Patapsco Valley State Park is one of many outstanding state parks in Maryland. Discover more parks in our Best State Parks in Maryland guide, or use our Park Finder to search by activity, location, or features.
⛺ Camping at Patapsco Valley State Park: Campgrounds & Cabins
| Campsites | Patapsco Valley State Park camping is split across two separate campground areas plus day-use pavilions elsewhere in the park (Avalon, Glen Artney, McKeldin, Orange Grove, Pickall are day-use/picnic-shelter areas only, not campgrounds). Hollofield area: 73 sites (inner loop electric, outer loop non-electric, mature-hardwood bluff setting) — CURRENTLY CLOSED for a multi-season renovation project (closed through the 2025 season and still closed as of Aug 2026, no confirmed reopening date). Hilton area: 12 non-electric tent-only sites plus 4 youth group sites. Park-wide reservation-system totals (when Hollofield is open): 30 electric campsites, 56 non-electric campsites, 4 mini cabins, 6 youth group sites, 43 picnic shelters across all areas; these totals could not be cleanly reconciled to a single park-wide site count while Hollofield is closed. |
|---|---|
| Cabins & Lodging | 4 mini cabins and 6 single-room camper cabins at Hilton (full-size bed plus bunk beds, baseboard heat, electric outlets, single overhead light; no bathroom/kitchen). |
| Pets | Pets allowed at most campsites; not permitted at the 6 youth group sites. |
| Reservations | Online at parkreservations.maryland.gov or 1-888-432-2267. Up to 365 days in advance, minimum 1 day ahead. Hilton: reservable April-October at $20-$50/night; open weekends only November-March. |
| Special sites | 6 youth group sites (Patapsco Valley-wide, capacity ~35 each). No RV maximum length published. Dump station on-site (Hollofield, closed with that area). |
| Season notes | Most camping March 27-October 31, 2026 (March 26-October 30, 2027) when open. Hollofield area campground closed for renovation (ongoing structural closure, no reopening date confirmed). Hilton open year-round but weekends-only Nov-March. |
Camping questions about Patapsco Valley State Park
Can you camp at Patapsco Valley State Park?
Patapsco Valley State Park camping is split across two separate campground areas plus day-use pavilions elsewhere in the park (Avalon, Glen Artney, McKeldin, Orange Grove, Pickall are day-use/picnic-shelter areas only, not campgrounds). Hollofield area: 73 sites (inner loop electric, outer loop non-electric, mature-hardwood bluff setting) — CURRENTLY CLOSED for a multi-season renovation project (closed through the 2025 season and still closed as of Aug 2026, no confirmed reopening date). Hilton area: 12 non-electric tent-only sites plus 4 youth group sites. Park-wide reservation-system totals (when Hollofield is open): 30 electric campsites, 56 non-electric campsites, 4 mini cabins, 6 youth group sites, 43 picnic shelters across all areas; these totals could not be cleanly reconciled to a single park-wide site count while Hollofield is closed.
How do you reserve a campsite at Patapsco Valley State Park?
Online at parkreservations.maryland.gov or 1-888-432-2267. Up to 365 days in advance, minimum 1 day ahead. Hilton: reservable April-October at $20-$50/night; open weekends only November-March.
Are there cabins at Patapsco Valley State Park?
4 mini cabins and 6 single-room camper cabins at Hilton (full-size bed plus bunk beds, baseboard heat, electric outlets, single overhead light; no bathroom/kitchen).
Are pets allowed at the Patapsco Valley State Park campground?
Pets allowed at most campsites; not permitted at the 6 youth group sites.
Source: parkreservations.maryland.gov (verified July 2026). Details change seasonally — confirm when booking.
🐾 Dogs & Pets at Patapsco Valley State Park
- Pets allowed? statewide rule
- Maryland state parks welcome leashed pets, but where they may go is set park by park under the Maryland Park Service Pet Policy — check each park's designated pet areas.
- Leash rule statewide rule
- 6 ft maximum in designated pet areas and 10 ft in undeveloped areas; off-leash under voice control only while swimming in designated areas
- Beaches & swim areas statewide rule
- At most parks pets are barred from sandy swim beaches from Memorial Day weekend through Labor Day; many parks allow shoreline swimming outside the swim beach
- Cabins & lodging statewide rule
- Most cabins are pet-free, but select parks designate pet-friendly cabins (e.g. Herrington Manor cabins 1-10, New Germany cabins 3-7)
- Statewide exceptions statewide rule
- Pets not allowed in park buildings or playgrounds; pets must be licensed and vaccinated
Are dogs allowed at Patapsco Valley State Park?
Maryland state parks welcome leashed pets, but where they may go is set park by park under the Maryland Park Service Pet Policy — check each park's designated pet areas. Individual parks can post stricter rules — check signage on arrival.
Rules verified July 2026 via dnr.maryland.gov. More: Maryland state parks guide · Dog rules in all 50 states compared
Park Location
Plan your gear for Patapsco Valley State Park
From our editorial guides, matched to this park’s activities:
