Help with Native American geneology

We have recently found out that my husband's great great Grandmother was Native American (previously he thought any Native American heritage was much further back), possibly Sioux.  We only have her Anglicised name that she took on when she married a white man.   Does anyone know how we might go about tracing her blood line?

Hi Britwife,

Do you know what region she was born in? That is a big start- many tribes have not moved for centuries.

Well after she was married she lived in Missouri so she probably came from there.

It is possible she was Missouri, but there were many other tribes, spread across the state.

Here is a page I found for you.

http://www.accessgenealogy.com/native/missouri/

I hate to say this, but some tribes don't like people from outside the reservation trying to dig this info up, and depending on the tribe, records can be scant. I am in the area of 1/3 Choctaw, and I know very little for this reason.

I was afraid of that but thanks so much for the link!