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]

WordNet (r) 3.0 (2006):

Ionia
    n 1: region of western Asia Minor colonized by ancient Greeks

U.S. Gazetteer Counties (2000):

Ionia -- U.S. County in Michigan
   Population (2000):    61518
   Housing Units (2000): 22006
   Land area (2000):     573.213835 sq. miles (1484.616954 sq. km)
   Water area (2000):    7.017770 sq. miles (18.175940 sq. km)
   Total area (2000):    580.231605 sq. miles (1502.792894 sq. km)
   Located within:       Michigan (MI), FIPS 26
   Location:             42.958883 N, 85.079273 W
   Headwords:
    Ionia
    Ionia, MI
    Ionia County
    Ionia County, MI


U.S. Gazetteer Places (2000):

Ionia, MO -- U.S. town in Missouri
   Population (2000):    108
   Housing Units (2000): 54
   Land area (2000):     0.153500 sq. miles (0.397563 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.153500 sq. miles (0.397563 sq. km)
   FIPS code:            35306
   Located within:       Missouri (MO), FIPS 29
   Location:             38.503911 N, 93.324261 W
   ZIP Codes (1990):     65335
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Ionia, MO
    Ionia


U.S. Gazetteer Places (2000):

Ionia, IA -- U.S. city in Iowa
   Population (2000):    277
   Housing Units (2000): 135
   Land area (2000):     0.558081 sq. miles (1.445424 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.558081 sq. miles (1.445424 sq. km)
   FIPS code:            38460
   Located within:       Iowa (IA), FIPS 19
   Location:             43.034493 N, 92.456606 W
   ZIP Codes (1990):     50645
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Ionia, IA
    Ionia


U.S. Gazetteer Places (2000):

Ionia, MI -- U.S. city in Michigan
   Population (2000):    10569
   Housing Units (2000): 2621
   Land area (2000):     5.042771 sq. miles (13.060717 sq. km)
   Water area (2000):    0.162914 sq. miles (0.421946 sq. km)
   Total area (2000):    5.205685 sq. miles (13.482663 sq. km)
   FIPS code:            40860
   Located within:       Michigan (MI), FIPS 26
   Location:             42.981932 N, 85.066792 W
   ZIP Codes (1990):     48846
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Ionia, MI
    Ionia