Peirce Mill is at 2375 Tilden St. N.W. at jct. Beach Dr. N.W., in Rock Creek Park. The 19th-century Peirce Barn, next to the mill, has exhibits about the history of milling on Rock Creek and the restoration work done on the mill. It's a good starting point for exploring the park; rangers can supply maps and directions.
Hours: Mill Wed.-Sun. 10-4, Apr.-Oct.; Sat.-Sun. 10-4, in Nov.; Sat.-Sun. noon-4, rest of year. Barn open second and fourth Sat. of the month 10-4, Apr.-Oct.; milling demonstrations are given 11-2. Closed Jan. 1, Thanksgiving and Christmas.