Patapsco River topographic map

Name: Patapsco River topographic map, elevation, terrain.

Location: Patapsco River, Riviera Beach, Anne Arundel County, Maryland, United States (39.15486 -76.61713 39.27449 -76.43622)

Average elevation: 7 m

Minimum elevation: -7 m

Maximum elevation: 51 m

The Patapsco River mainstem begins at the confluence of the North and South Branches, near Marriottsville, approximately 15 miles (24 km) west of downtown Baltimore. The 19.4-mile-long (31.2 km)[1] South Branch rises further west at Parr's Spring, where Howard County, Carroll, Frederick, and Montgomery counties meet. The latter begins at elevation 780 feet (240 m) on Parr's Ridge, just south of Interstate 70 and east of Ridge Road (Highway 27), 2 miles (3 km) south of Mount Airy, Maryland.[1] The South Branch Patapsco River traces the southern boundary of Carroll County and the northern boundary of Howard County. The first land record regarding Parr's Springs dates from 1744, when John Parr laid out a 200 acres (81 ha) tract he called Parr's Range. During the Civil War, Parr's Spring was a stop for the Army of the Potomac's Brig. Gen. David M. Gregg's cavalry, on June 29, 1863, while en route to Gettysburg, Pennsylvania.[9] Parr's Spring was dug to form a 1.75 acres (7,100 m2) pond in the 1950s, filled by seven spring heads that form the headwaters of the South Branch of the Patapsco River.[10]