Combine Two Shapefiles?

[KenFlerlage]

I'm new to GIS and have what may be a stupid question. I have two shapefiles, one showing the US states from 1789 and one showing the US states from today. I'd like to combine them into a single file, with a new field indicating the year. I've played with the merge function but that seems to merge them together into a single set of shapes, whereas I want to keep them as distinct sets of data, just in a single file. In SQL terms, I'm looking for a UNION ALL, as opposed to a UNION.

[DanPatterson_Retired]

To keep the instructions simple, I will direct you to two tools in arctoolbox... Add Join ... and the ... Spatial Join ...

The most appropriate will depend on your attribute table content and arrangement and the degree to which you can associate geometries between the two time periods.

[AbdullahAnter]

Why do you want to combine them?

it is cause overlap or change the shape (union method)

[KenFlerlage · Accepted solution]

I ended up using the Append function. I used "Add Field" to add a new field to each shapefile, which would identify that shapefile. I then use "Calculate Field" to populate it with said identifier. From there, I just did an append to put them together into a single file. Thanks for the input everyone!