He became one of the wealthiest ranchers in California, and was among the highly influential men who worked to gain United States statehood after Mexico ceded this area following its defeat in the Mexican-American War.

[3][4] Marsh knew Hebrew, Latin and Greek, and, while working as a US Indian agent at Fort Snelling, was the first person to compile a dictionary of the Siouan language.

Born in Danvers, Massachusetts in 1799, Marsh graduated from the private Phillips Academy in Andover in 1819.

Marsh migrated west, living in the Michigan Territory, where he opened a school, the first in what is now Minnesota.

[8] Marsh lived for a time in Prairie du Chien, Wisconsin, where he got involved in the Black Hawk War between the United States and a group of Sauk, Meskwaki (Fox), and Kickapoo, known as the "British Band".

Marsh placed his young son, Charles, to be raised with a family named Painter in New Salem.

He was discovered selling guns illegally to some of the Indians and had to flee the territory, this time settling in Independence, Missouri, where he became a merchant.

Marsh visited his son again before his business failed, and in 1836 he emigrated, as an employee of the American Fur Company, to Santa Fe, New Mexico.

In southern California, Marsh claimed he was the only person who had any knowledge of Western (or European-style) medicine.

In 1836, he sold his accumulated inventory to a Boston trader for $500 and rode to Northern California seeking a ranch to purchase.

In practicing medicine, he again charged very high prices, generally in relation to how far he had to travel to see the patient (which often meant being away from his ranch for days or weeks).

Marsh acquired tens of thousands of head of cattle for his rancho and lived the life of a wealthy ranchero.

[24][25] After entertaining members of the Bartleson-Bidwell Party, Marsh was said to invite them to slaughter one of his steers for breakfast the next morning.

The next day, however, he found that the party had also slaughtered his best work oxen, which comprised a highly valuable commodity and were critical to ranch operations.

Americans and some other foreigners considered the Mexican courts in California to be corrupt and unpredictable in their rulings on such cases.

In addition, there was evidence of competition by the Russians, French and English, who were independently preparing to seize the province.

His letters were read, reread, passed around, and printed in newspapers throughout the country, and stimulated the first significant migration to California.

[34][35][4] Marsh worked behind the scenes to promote American statehood, at the urging of U.S. consul Thomas O. Larkin.

In March 1845 he wrote a letter signed by himself and 23 other expatriates, announcing a clandestine meeting for the Fourth of July.

[37] Marsh soon began construction of a mansion built entirely of stone quarried from the nearby hills.

Abby chose to site the house next to Marsh Creek, with a fine view of the surrounding valley and Mount Diablo.

On September 24, 1856, he began a journey from his land in eastern Contra Costa County to San Francisco for a personal or political appointment.

According to local tradition, shortly before Marsh's death, a young man arrived at his house, saying he was seeking shelter from a harsh storm.

As a young woman, Alice Marsh moved to Oakland, where she married William Walker Camron, one of the builders of the Mt.

[37] She and Amy (who remained unmarried) operated a San Francisco boardinghouse, and later moved to Santa Barbara.

[45] A non-profit known as the John Marsh Historic Trust was organized to preserve structures and areas associated with his history in the state.