Dogs are welcome at Patuxent River Park in Gaithersburg, Maryland. This pretty park is made up of 6,700 acres of natural areas and farmlands, with a section of the park dedicated as a state wildlands area. There are unmarked trails that weave around the classic Maryland landscape, perfect for exploring with your pooch. You can bring Fido with you, as long as they are on a leash and all mess is cleaned up after them. Patuxent River Park is open every day of the week from sunrise to sunset.