The Collaborative International Dictionary of English v.0.48:

Ionia \Ionia\ n.
   A region of Western Asia Minor colonized by the Ancient
   Greeks.
   [WordNet 1.5]

U.S. Gazetteer (1990):

Ionia, IA (city, FIPS 38460)
  Location: 43.03625 N, 92.45764 W
  Population (1990): 304 (134 housing units)
  Area: 1.4 sq km (land), 0.0 sq km (water)
  Zip code(s): 50645
Ionia, KS
  Zip code(s): 66949
Ionia, MI (city, FIPS 40860)
  Location: 42.98510 N, 85.05797 W
  Population (1990): 5935 (2412 housing units)
  Area: 7.3 sq km (land), 0.2 sq km (water)
  Zip code(s): 48846
Ionia, MO (town, FIPS 35306)
  Location: 38.50385 N, 93.32280 W
  Population (1990): 126 (55 housing units)
  Area: 0.4 sq km (land), 0.0 sq km (water)
  Zip code(s): 65335
Ionia, NY
  Zip code(s): 14475