From Wikipedia:
Japanese operations
[edit] Bombardment of Ellwood
The United States mainland was first shelled by the Axis on February 23, 1942 when the Japanese submarine I-17 attacked the Ellwood Oil Field west of Goleta, near Santa Barbara, California. Although only a pumphouse and catwalk at one oil well were damaged, I-17 captain Nishino Kozo radioed Tokyo that he had left Santa Barbara in flames. No casualties were reported and the total cost of the damage was officially estimated at approximately $500–1,000.[1] News of the shelling triggered an invasion scare along the West Coast.[2]
[edit] Bombardment of Estevan Point lighthouse
On June 20, 1942, the Japanese submarine I-26, under the command of Yokota Minoru[3], fired 25-30 rounds of 5.5" shells at the Estevan Point lighthouse on Vancouver Island in British Columbia, but failed to hit its target.[4] This marked the first enemy shelling of Canadian soil since the War of 1812. Though no casualties were reported, the subsequent decision to turn off the lights of outer stations was disastrous for shipping activity.[5]
[edit] Bombardment of Fort Stevens
See also: Bombardment of Fort Stevens
In what became the only attack on a mainland American military installation during World War II, the Japanese submarine I-25, under the command of Tagami Meiji,[3] surfaced near the mouth of the Columbia River, Oregon on the night of June 21 and June 22, 1942, and fired shells toward Fort Stevens. The only damage officially recorded was to a baseball field's backstop. Probably the most significant damage was a shell that damaged some large phone cables. The Fort Stevens gunners were refused permission to return fire, since it would have helped the Japanese locate their target more accurately. American aircraft on training flights spotted the submarine, which was subsequently attacked by a US bomber, but it escaped.
[edit] Lookout Air Raid
Main article: Lookout Air Raid
Nobuo Fujita standing by his Yokosuka E14Y "Glen" seaplane.
The Lookout Air Raid occurred on September 9, 1942. The first and only aerial bombing of mainland America by a foreign power occurred when an attempt to start a forest fire was made by a Japanese Yokosuka E14Y1 seaplane dropping two 80 kg (180 lb) incendiary bombs over Mount Emily, near Brookings, Oregon. The seaplane, piloted by Nobuo Fujita, had been launched from the Japanese submarine aircraft carrier I-25. No significant damage was officially reported following the attack, nor after a repeat attempt on September 29.
Here's the link:
http://en.wikipedia.org/wiki/Attacks_on_North_America_during_World_War_II