From Ancestry.com Wiki
This entry was originally written by Dwight A. Radford for Red Book: American State, County, and Town Sources.
No common port of entry existed for overseas immigrants who settled in Idaho, nor were there any railroads or emigration trails. Those who arrived and remained in Idaho developed their society in relative isolation. Idaho did have one port of entry at the Canadian border through which immigrants could migrate. By 1924 Idaho was under the jurisdiction of the Spokane, Washington, Office of the Bureau of Immigration. Port of entry was at Eastport, Idaho. Eastport records are filed with the Seattle passenger lists (1890–1957) at the National Archives. These have been microfilmed but are not indexed. Additional information on people entering through Eastport, Idaho, may be obtained from a search of the (so-called) St. Albans, Vermont District records (see Vermont Immigration), which are indexed.