Martha McLean – Anza Narrows is a 40-acre (0.16 km2; 0.063 sq mi) regional park located along the Santa Ana River in Riverside, California, United States. The park is operated by the City of Riverside - Parks Recreation and Community Services Department. A plaque in the northwest corner of the park marks the point at which the Juan Bautista de Anza party, the first Europeans to traverse the Riverside area, crossed the river in 1774 and again in 1776.