Probably — and this is not only applied to reservations but to many rural communities. There are parts of the US where people just did not traditionally have an address of the form “(Road Name/Number), (House Number)” on a fixed baseline grid.
In drawing up the election districts, precincts and wards, the states will make the division discrete only to the Census Tract level, rather than to the house-by-house level if they don’t have to. So they refer to THAT map where generally any clustered community will be one tract.
If it’s a small reservation, its tracts may add up to a self-contained single ward anyway.
In a larger reservation or just a larger rural area you may have an issue if Mr. Voter lives in a cabin on a hill exactly three miles from the closest neighbor in each direction and the last mile is by mule trail, but somewhere the local authority has a map saying what tract amd ward he’s in.
If the various authorities have their act together, in such communities the local authorities will sit with the postmaster and draw up a distribution, by which for instance, residents in tract 1 will be on postal route 11, boxes numbered 10***, tract 2 will be on postal route 11, Boxes numbered 20***, tract 3 will be postal route 11, Boxes 30*** and so forth, and the elections apportionment people will use that to define who is in what district.