The state government did not improve the gravel county roads that encompassed SSH 11A, but did relocate its toll-free ferry from White Bluffs to Hanford in May 1938. The Hanford ferry was initially planned to use a cable-operated system, but costs forced it to be downgraded to a tug-and-barge ferry. During World War II, the U.S. military selected the Hanford area as the site of a major weapons development facility and a section of SSH 11A was acquired via a request of the Secretary of War filed on July 21, 1943. The section, located between Cold Creek and Hanford, was closed permanently to non-military traffic on November 15, 1943, and divided SSH 11A into two disconnected highways. The rest of the highway had been paved by the state government in the early 1940s, with the exception of a section west of Connell that remained gravel.