Post Offices List in Clark County, Illinois:

Casey Post Office	100 W Alabama Ave, Casey, IL 62420
Marshall Post Office	115 N 7th St, Marshall, IL 62441
Martinsville Post Office	2 N York St, Martinsville, IL 62442
West Union Post Office	211 W Union St, West Union, IL 62477
Westfield Post Office	130 W State St, Westfield, IL 62474