The K. O. Knudson Photographs (approximately 1920-1969) depict the Las Vegas Grammar School and service, fraternal, and veterans organizations gathered by retired Las Vegas, Nevada school administrator and World War I veteran K. O. Knudson (also known as K. Oscar Knudson). The collection includes images of Knudson, Las Vegas Masonic Lodge members, American Legion members, and school dances. The photographs primarily feature Las Vegas, Nevada.