The Collaborative International Dictionary of English v.0.48:

Hidalgo \Hi*dal"go\, n. [Sp., contr. fr. hijo de algo, i. e.,
   son of something; hijo son (fr. LL. filius) + algo something,
   fr. L. aliquod. Cf. Fidalgo.]
   A title, denoting a Spanish nobleman of the lower class.
   [1913 Webster]

U.S. Gazetteer Counties (2000):

Hidalgo -- U.S. County in New Mexico
   Population (2000):    5932
   Housing Units (2000): 2848
   Land area (2000):     3445.633240 sq. miles (8924.148744 sq. km)
   Water area (2000):    0.279146 sq. miles (0.722985 sq. km)
   Total area (2000):    3445.912386 sq. miles (8924.871729 sq. km)
   Located within:       New Mexico (NM), FIPS 35
   Location:             32.025077 N, 108.736570 W
   Headwords:
    Hidalgo
    Hidalgo, NM
    Hidalgo County
    Hidalgo County, NM


U.S. Gazetteer Counties (2000):

Hidalgo -- U.S. County in Texas
   Population (2000):    569463
   Housing Units (2000): 192658
   Land area (2000):     1569.746365 sq. miles (4065.624249 sq. km)
   Water area (2000):    12.917617 sq. miles (33.456472 sq. km)
   Total area (2000):    1582.663982 sq. miles (4099.080721 sq. km)
   Located within:       Texas (TX), FIPS 48
   Location:             26.242291 N, 98.159799 W
   Headwords:
    Hidalgo
    Hidalgo, TX
    Hidalgo County
    Hidalgo County, TX


U.S. Gazetteer Places (2000):

Hidalgo, IL -- U.S. village in Illinois
   Population (2000):    123
   Housing Units (2000): 62
   Land area (2000):     0.343399 sq. miles (0.889399 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.343399 sq. miles (0.889399 sq. km)
   FIPS code:            34553
   Located within:       Illinois (IL), FIPS 17
   Location:             39.156628 N, 88.150697 W
   ZIP Codes (1990):     62432
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Hidalgo, IL
    Hidalgo


U.S. Gazetteer Places (2000):

Hidalgo, TX -- U.S. city in Texas
   Population (2000):    7322
   Housing Units (2000): 1880
   Land area (2000):     4.352536 sq. miles (11.273017 sq. km)
   Water area (2000):    0.087672 sq. miles (0.227069 sq. km)
   Total area (2000):    4.440208 sq. miles (11.500086 sq. km)
   FIPS code:            33560
   Located within:       Texas (TX), FIPS 48
   Location:             26.104473 N, 98.246443 W
   ZIP Codes (1990):     78557
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Hidalgo, TX
    Hidalgo