The Luiseño Indians, who first occupied the land around Lake Elsinore, knew the water by the musical name Etengvo Wumoma. When Spaniards came, they gave the lake the name Laguna Grande, or Big Lagoon. The first American settlers changed the name to Elsinore.

In 1844, the king of Spain gave a land grant of almost 20,000 acres to Julian Manriquez. He sold the land to Abel Stearns, a California land baron, who subsequently sold it to Augustin Machado in 1858.

The Machado family built an adobe home on the south side of the water. The adobe bricks were barely dry when the U.S. Legislature authorized the establishment of the Butterfield Overland Mail stage line. It was created to carry mail from St. Louis, Missouri to San Fransisco, California—the first trip took 21 days. The Machado home was a regular stop for the stage so it’s drivers could rest, eat, and change horses. Today, the home still exists near the curve of Grand Avenue and Riverside Drive.

Franklin Heald saw Lake Elsinore from Mt. Baldy in the early 1880s. With his partners, they purchased the Rancho Laguna land grant for $24,000 in 1883, incorporating the community in April 1888 as the City of Elsinore. At this time, Elsinore was part of San Diego County. After many proposals, the County of Riverside was created by the California Legislature in March 1893 and the new county began doing business effective July 1, 1893. To create the new county, land was taken from both San Bernardino and San Diego Counties.