Japantown was depopulated during the forced incarceration of Japanese and Japanese-Americans following the issuance of Executive Order 9066 in 1942, and was re-filled by Filipino and Mexican laborers, who took over work in local orchards and farms during the war.

[1] On October 7, 1915, fire swept through the Chinatown district in Walnut Grove, including Japantown, and shifting winds were credited with confining the damage to the Dye Brothers-owned "Oriental quarter" and not destroying the remainder of the town.

[1][2] Unlike other local nihonmachi, Asians were credited with designing and building the new Kawashimo,[1] with some coming from as far away as San Francisco to participate in the rebuilding.

[6][7] The district was forcibly depopulated in the wake of Executive Order 9066[1][4] and repopulated with Filipino and Mexican laborers during World War II.

[4] After the end of the war, many of the original residents returned but most did not remain in Walnut Grove, attracted by opportunities in nearby cities.