David 'Dave' Christian Farnsworth (born July 16, 1951 in Mexico City, Mexico) is an American politician and a Republican member of the Arizona Senate representing District 16 since his appointment September 11, 2013 to fill the vacancy caused by the resignation of Rich Crandall. Farnsworth served non-consecutively in the Arizona State Legislature from January 1995 until January 1997 in the Arizona House of Representatives District 4 seat.