Susquehanna State Park and the Rock Run Grist Mill in Havre de Grace, MD: Trails, Fees and Hours

by Josh Tessier

Published Oct. 30, 2026 | Last updated: Oct. 30, 2026

Susquehanna State Park is a Maryland state park about 3 miles northwest of Havre de Grace, off Route 155. You get more than 15 miles of trails, river fishing and the Rock Run Historic Area, home of a working grist mill from around 1800. The park lists day-use fees only at the Deer Creek Picnic Area and the Lapidum Boat Launch area.

Here's the catch for this time of year. The mill and mansion only open on summer weekends, so in the fall and winter you're there for the trails, the river and the old buildings from the outside.

What is Susquehanna State Park?

It's a state park run by the Maryland Department of Natural Resources along the Susquehanna River valley. The land is wooded and rocky. Here's what you get:

More than 15 miles of marked trails for hiking, mountain biking and horseback riding
The Rock Run Historic Area: the grist mill, the Carter-Archer Mansion, the Jersey Toll House and what's left of the Susquehanna and Tidewater Canal
The Deer Creek Picnic Area with a pond for new anglers
A campground with sites and camper cabins
The Lapidum Boat Ramp on the river

What is the Rock Run Grist Mill?

John Stump built the Rock Run Grist Mill around 1800. It stands four stories tall and has 34 windows. It was a merchant mill, so it ground wheat into flour for buyers near and far. The park says a lot of that flour went to the Caribbean.

A fun fact: the mill's second floor was the local post office from 1827 to 1856. The old mail windows and boxes are still there. The state bought the mill in 1960, and its corn grinding was partly restored for public shows in 1965.

https://cdn.lofty.com/image/fs/400919269340348/website/158564/cmsbuild/20261030_fe570831d8344c0a.jpeg

The four-story stone Rock Run Grist Mill with bare fall trees at Susquehanna State Park — *The Rock Run Grist Mill in late November.*
Photo: “Rock Run Grist Mill (looking SE)” by engineerchange, licensed under CC BY 2.0, via Wikimedia Commons. Taken November 2022. Resized.

When is the Rock Run Grist Mill open?

The park's walking tour guide lists these building hours, on weekends from Memorial Day weekend through Labor Day:

Grist mill: 10 a.m. to 4 p.m.
Carter-Archer Mansion: 1 p.m. to 4 p.m.

Private mill and mansion tours are also available on request. The grounds around the Carter-Archer Mansion follow the same gate hours as the Deer Creek Picnic Area (see hours below). Call (410) 557-7994 to ask. Confirm before you go.

What are the best trails?

The park lists trails from easy to hard. Here are a few:

Trail	Blaze	Length	Level
Susquehanna Ridge Trail	Red	About 3 miles	Moderate to hard
Deer Creek Trail	Green	2.1 miles	Moderate to hard
Farm Road Trail	Dark blue	2 miles	Moderate
Ivy Branch Trail	Orange	2 miles	Easy to moderate
Land of Promise	White	1.6 miles	Moderate
Rock Run Y Trail	Yellow	0.9 miles	Moderate

Want flat and easy? Take the Lower Susquehanna Heritage Greenways Trail. It runs between the Conowingo Dam and Stafford Road at Deer Creek, and it's handicapped accessible. Good to know right now: the footbridge near the Stafford Flint Furnace is closed after storm damage. Use the Deer Creek trestle bridge at 851 Stafford Rd. instead. Confirm before you go.

What does Susquehanna State Park cost?

DNR lists these day-use and launch fees. It does not list an entry fee for the rest of the park.

Area	Maryland residents	Out of state
Deer Creek Picnic Area and Lapidum Boat Launch area (day use)	$2 per vehicle	$4 per vehicle
Launching a boat at Lapidum	$10 per vehicle	$12 per vehicle

Confirm before you go.

What are the hours?

The park is open sunrise to sunset. The Deer Creek Picnic Area and the Carter-Archer Mansion area open at 10 a.m. from November through March and at 9 a.m. from April through October. Fishing and boat launching are allowed outside normal hours, so check with the park first if you plan to go early or late.

Can you camp at Susquehanna State Park?

Yes, but not until spring. The campground runs from the first weekend in May through the last weekend in October. It has 69 sites, six with electric, plus six camper cabins and hot showers. Pets on a leash are allowed in the campground and cabins. Base rates are $21.50 for a site, $27.50 with electric, and $50.50 for a mini cabin, before fees. Book at parkreservations.maryland.gov. Confirm before you go.

Can you fish there?

Yes. Depending on the season, you can catch striped bass, largemouth and smallmouth bass, perch, catfish and carp. The shad and herring runs in early spring are a big show.

You need the right license. The river from the Conowingo Dam to the bay is tidal, so you need a Chesapeake Bay and Coastal Sport License. Deer Creek needs a non-tidal license.

Are dogs allowed?

Yes. DNR says pets are allowed in all areas of the park, including the campground and cabins, but they must stay on a leash.

My plan for a fall day at Susquehanna

Park at Rock Run and walk around the mill and toll house.
Walk the Greenways Trail or the Deer Creek Trail.
Drive into Havre de Grace for dinner. Check my Havre de Grace holiday guide for what's going on downtown.

Want more? See my Christmas tree farms guide and the Turkey Trots in Harford County. You can find every post on my Harford County blog.

What's it like living near Susquehanna State Park?

You get river views, small-town shops and fast access to I-95. Homes in Havre de Grace, Darlington and Aberdeen are close to the park. If you want to live near the water, I'll help you find the right spot. Call or text me at (443) 617-2099.

FAQ

Where is Susquehanna State Park?

The park office is at 4122 Wilkinson Rd., Havre de Grace, MD 21078. The Rock Run Grist Mill is at 801 Stafford Rd.

Is Susquehanna State Park free?

DNR lists fees only at the Deer Creek Picnic Area and the Lapidum Boat Launch area. Day use there is $2 per vehicle for Maryland residents and $4 for out-of-state visitors. Launching a boat at Lapidum is $10 or $12.

When is the Rock Run Grist Mill open?

The mill is open 10 a.m. to 4 p.m. on weekends from Memorial Day weekend through Labor Day. Private tours are also available on request.

How many miles of trails does Susquehanna State Park have?

The park has more than 15 miles of marked trails for hiking, mountain biking and horseback riding.

Can you camp at Susquehanna State Park in the winter?

No. The campground is open from the first weekend in May through the last weekend in October.

Are dogs allowed at Susquehanna State Park?

Yes. Pets are allowed in all areas of the park, including the campground and cabins, but they must stay on a leash.

About the author: Josh Tessier is a Harford County REALTOR® with the Lee Tessier Team at eXp Realty, based in Bel Air. He has 16+ years in real estate and has sold 600+ homes personally (5,900+ for the Lee Tessier Team). He lives in Harford County and is raising his family here. Call or text (443) 617-2099.

Harford County real estate agent Josh Tessier — *Josh Tessier, REALTOR® with the Lee Tessier Team. Call or text (443) 617-2099.*

Watch more on my YouTube channel, Josh Talks Harford, and follow along on Facebook and Instagram.

Header photo: “Rock Run Grist Mill (looking NW)” by engineerchange, licensed under CC BY 2.0, via Wikimedia Commons. Taken Nov. 25, 2022. Cropped, with text added.