Click the Edit search if you want to search by County, Enumeration District or Keywords.
There are five counties: Eastern District of Tutuila, Manua. Rose Island, Swains Island and Western District of Tutuila County.
There is a advanced search button to the right top of the screen
if you want to search by roll and/or frame.
Other sites to view the 1940 US Census are Ancestry.com. FamilySearch has Alabama, Colorado, Delaware, Florida, Kansas, Oklahoma, Oregon, and Virginia. Findmypast.com don't have anything online as of now, but are offering to do the searching for you.
All images used in this blog post are from the MyHeritage.com