I'm interested in locating free GIS shapefile data representing the US / Mexican border. I have found a point layer depicting the border crossing points but I'm interested in a polyline feature representing the actual border.
You can obtain the line shapefile for the Mexican border from the U.S. Geological Survey website (or click here directly). Scroll down and from the list of Categories, select the Boundaries option. Then from the Int Boundary layer, click the Shapefile link:
You will also get the length of each line feature (as the boundary is broken up into segments).
Hope this helps!
Sometimes INEGI can help! from our side (México), and depends of what you want to do with that, look in this site:
click in "Areas geoestadisticas estatales"
There are a multitude of potential sources for this, but the US State Department Office of the Geographer is the authoritative US source for international boundaries. The Large Scale International Boundaries (LSIB) dataset is the reference work from which all maps generated by the US government are to be derived. The Humanitarian Information Unit has a distribution website for LSIB data.
For country borders and those on lower administrative levels, have a look at gadm. I think the datasets are free for non-commercial use.
International Boundary & Water Commission USA and Mexico has a link of GIS.