The Mussel Slough Tragedy was a dispute over land titles between settlers and the Southern Pacific Railroad (SP) that took place on May 11, 1880, on a farm located 5.6 miles (9 km) northwest of Hanford, California, in the central San Joaquin Valley, leaving seven people dead. The site of the episode is now registered as California Historical Landmark #245. A historical marker on the east side of 14th Avenue, 350 yards (320 m) north of Elder Avenue, memorializes the site.