Madera is a city and county seat of Madera County, located in the San Joaquin Valley of California. As of the 2020 United States census, th…Madera is a city and county seat of Madera County, located in the San Joaquin Valley of California. As of the 2020 United States census, the city's population was 66,224. The town was named after the Spanish term for lumber. The town was laid out by the California Lumber Company in 1876. From 1876 to 1931, a 63-mile water flume carried lumber from the mountains to Madera, where the lumber was shipped by train.