Rancho Huasna was a 22,153-acre (89.65 km2) Mexican land grant in present-day San Luis Obispo County, California given in 1843 by Governor Manuel Micheltorena to Isaac J. Sparks.[1] The grant extended along the Huasna River and the western slope of the Santa Lucia Range, east of present-day Arroyo Grande and encompassing Huasna.[2][3][4]