Filmed in a house called "Cliff House" designed by famed architect Frank Lloyd Wright. It was the home of the film's producer/writer/director, Arch Oboler, and sat on his 360-acre ranch in the Santa Monica Mountains along Mulholland Highway. Outdoor scenes were filmed on his property as well as other nearby locations in the Santa Monica Mountains. The "Cliff House" was burned to the ground - with only the foundations and chimney remaining - in the 2019 Woolsey Fire which swept through the area.
According to TCM's Robert Osborne, this is the first feature film to depict the aftermath of a nuclear holocaust.
The beach scene where Eric washes ashore was filmed at Westward Beach. This was the same beach where Charlton Heston encounters the ruins of the Statue of Liberty in "Planet of the Apes" (1968). In the long shots, the rocks visible in the distance were to the left of the statue.
The verse that appears on screen just after the title card and footage of atomic blasts is from Psalm 103:16 from the Bible (King James Version): "The deadly wind passeth over it / And it is gone; / And the place thereof / Shall know it no more..." Note the insertion of the word "deadly" which does not appear in the Bible.
Charles' soliloquy is taken from the poem "The Creation" by noted African-American professor and diplomat James Weldon Johnson (1871-1938). It is part of his work "God's Trombones" published in 1927.