Lathrop is a city located 9 miles (14 km) south of Stockton in San Joaquin County, California, United States. The 2010 United States Census reported Lathrop's population was 18,023. The city is located in the San Joaquin Valley in Northern California at the intersection of Interstate 5 and SR 120.
Lathrop was platted when the transcontinental railroad was extended to that point around 1868. A post office has been in operation at Lathrop since 1871. The city was named for Jane Stanford, née Lathrop, wife of Leland Stanford.
On September 6, 1869, four months after the golden spike ceremony of the first transcontinental railroad at Promontory Summit, the San Joaquin River Bridge at Mossdale crossing at Lathrop was finished by Western Pacific. This actually completed the last link of the transcontinental railroad to the Pacific coast with the first through train from Sacramento arriving that evening at the Alameda Wharf in San Francisco Bay.
On August 14, 1889, former Chief Justice of California David S. Terry assaulted United States Supreme Court Justice Stephen J. Field, at the train station in Lathrop. Field's bodyguard, United States Marshal David Neagle (formerly assigned to Tombstone, Arizona), shot and killed Terry. The events led to the United States Supreme Court decision In re Neagle, which granted immunity from State prosecution to federal officers acting within the scope of their federal authority.
Lathrop is located at 37°49′1″N 121°17′19″W (37.816904, -121.288633). The San Joaquin River is on the west side of Lathrop and has elevation of 20 feet (7 m).