Any unincorporated area contiguous to a second-class city or town may be annexed thereto by an ordinance accepting a gift, grant, or lease from the government of the United States of the right to occupy, control, improve it or sublet it for commercial, manufacturing, or industrial purposes: PROVIDED, That this shall not apply to any territory more than four miles from the corporate limits existing before such annexation.
RCW 35.13.190
Validating-1915 c 13: "All ordinances heretofore passed by the legislative authority of any such incorporated city for the purpose of accepting any gift, grant or lease of or annexing any territory as hereinabove provided are hereby validated." [ 1915 c 13 s 3.]