Why can't I find immigration records?

Question:

Why can't I find immigration records?

I have been searching for my ancestors names on passenger lists and for their naturaliztion paperwork. I have tried every possible spelling and nothing comes up. My Great Grandfather had a SS card and served in WWI so he would have to have been a citizen, but why can't I find any info on him.

This may be useful:

B. 1894 in Mannheim, Germany
Arrived 1899
Listed himself as a naturalized citizen on several census forms
Lived in Minnesota until around 1910, and moved to Idaho and stayed there until he died in 1981

Best Answer - Chosen by Asker: Here are some reasons you might not have found him:

He entered through a port you haven't yet searched.
He immigrated to Canada and then crossed the border into Minnesota.
His name was different at the time he immigrated than the name he used lated in life.
His name is misspelled on the record.
His name is misindexed in the index.
His family immigrated under a pseudonym to avoid financial, legal, or military problems.
The manifest on which he was listed was lost or destroyed.

There are lots more reasons.

Right now, through the end of November, Ancestry.com is offering free access to their immigration collection which contains indexed digital images of all easily obtainable US passenger manifests (not just Ellis Island). So, if you haven't already checked out this resource, do so now!

Another option is to look for naturalization papers. the naturalization record should tell you the name of the ship and the date of immigration. Since he was born in 1894 and moved to Idaho in 1910, he would have been naturalized in Idaho. Check the microfilms for Idaho naturalization records at the Family History Library (you can borrow these through a Family History Center near you). The Family History Library has the following naturalization records:

Naturalization records, Central District, Moscow, Idaho, 1892-1935 United States. District Court (Idaho)

Naturalization records, Eastern District, Pocatello, Idaho, 1893-1945 United States. District Court (Idaho)

Naturalization records, Northern District, Coeur d'Alene, Idaho, 1909-1929 United States. District Court (Idaho)

Naturalization records, Southern District, Boise, Idaho, 1891-1934 United States. District Court (Idaho)

One last point: a person did not have to be a citizen to have a social security card or serve in the military.