Gateway Park is a small urban park located in Medford along the banks of the Mystic River. It is part of the Mystic River Reservation. Gateway Park features a playground, a basketball court, a picnic area, and a boat ramp that provides access to the river. The park is also a gateway to the Mystic River Bike Path, a 10-mile trail that connects to other parks and trails in the region.

The Mystic River Reservation is open year-round, from dawn to dusk. The banks of the Mystic River are almost entirely publicly owned, from the Amelia Earhart Dam at the mouth of the Mystic Lakes, making it one of the Commonwealth's best-protected streams. The river has been much altered since the 1800s when its shores were largely salt marsh.

Each spring, starting in mid-May and running through the end of June, there is an impressive run of Alewives and Blueback Herring up the Mystic River and into Lower Mystic Lake. This creates a tremendous food source for gulls, cormorants, and, most impressively, Black-crowned Night-Herons.

Open year-round, dawn to dusk. The banks of the Mystic River are almost entirely publicly owned, from the Amelia Earhart Dam at the mouth of the Mystic Lakes, making it one of the Commonwealth’s best-protected streams. The river has been much altered since the 1800s when its shores were largely salt marsh.