'O'Brien County' definitions:
O'Brien -- U.S. County in Iowa
From: Gazetteer 2000
Name :
O'Brien -- U.S. County in Iowa
Population (2000) :
15102
Housing Units (2000) :
6509
Land area (2000) :
573.078149 sq. miles (1484.265528 sq. km)
Water area (2000) :
0.171193 sq. miles (0.443388 sq. km)
Total area (2000) :
573.249342 sq. miles (1484.708916 sq. km)
Located within :
Iowa (IA), FIPS 19
Location :
43.090091 N, 95.639384 W