Spoiler warning: Plot and/or ending details follow.
Mojave is a city located in the southwestern region of the United States of America in California.
The city, historically in a desert region, by the 23rd century was surrounded by areas of lush parkland. The most impressive parklands were concentrated around the cities of the region. (TOS episode: "The Cage")
Josh Pike and his wife made their home in a ranch near the city which was situated amongst more typically arid conditions of the region, though close enough to engineered environments that one could ride out into the forests and grasslands near by. Their son Christopher Pike, future Captain of the USS Enterprise, was born in Mojave and used to ride his horse Tango around the parklands. (TOS episode: "The Cage"; EV comic: "The Fallen")
When the Talosians captured Christopher Pike in 2254 they created a mental illusion of Mojave, where Pike was to have a picnic with fellow captive Vina in the hopes of having the pair mate and stay in Talosian captivity. (TOS episode: "The Cage")