DEM of Butler County,OH

[Houxiang Wang GEO Grad 96]

Hello everyone:

	I am currently working on a project. The DEM I am using is of 50*50m 
resolution which is not high enough. Does anyone know where I can get for free a 
better (30 by 30m) DEM or other format of data from which I can generate slope 
and aspect? 
	
Thanks,

Houxiang