Old Mission Dam

	Old Mission Dam
	U.S. National Register of Historic Places
	U.S. National Historic Landmark
	California Historical Landmark No. 52
	San Diego Historic Landmark No. 2
	Old Mission Dam in 2008
Location	Mission Trails Regional Park, San Diego, California
Coordinates	32°50′24″N 117°2′32″W / 32.84000°N 117.04222°W
Area	0.3 acres (0.12 ha)
Built	1803
NRHP reference No.	66000225
CHISL No.	52
SDHL No.	2
Significant dates
Added to NRHP	October 15, 1966
Designated NHL	May 21, 1963
Designated CHISL	December 6, 1932
Designated SDHL	February 1, 1968

Old Mission Dam is a historic water impoundment structure in Mission Trails Regional Park in San Diego, California. It was built in 1803 to impound the San Diego River to provide water for irrigation of the fields associated with Mission San Diego de Alcalá, the first Spanish mission in what is now the US state of California. It was the first major colonial-era irrigation project on the Pacific coast of the United States. The surviving remnant of the dam was designated a National Historic Landmark in 1963.