Hi Gordon,
Have you looked at the GRASS FAQ html page? It discusses importing the
USGS 1:250000 DEM, you can find the FAQ at:
http://softail.cecer.army.mil/grass/faq.html
I hope this helps.
Louis Clarke U.S. Army Corps of Engineers
lclarke@alb-co-r.swa.usace.army.mil Albuquerque District
voice (505) 342-3281 Regulatory Branch
fax (505) 342-3498