Lilac Park is an unincorporated community in Arnold, California in Calaveras County, California. Lilac Park Subdivision was approved by the CA Dept of Real Estate in February 1956. Arnold Lilac Park Homeowners Association (ALPHA) was incorporated on February 23, 1959. There are 205 home sites in ALPHA, not all are improved. The east side of Lilac Park sits atop Rocky Ridge (aka Grizzly Ridge) and the west side follows SR 4. The community rests on a west facing slope.