Boulder Hill is an unincorporated area of Kendall County. According to Wikipedia, Boulder Hill has a total area of 1.45 square miles. The community itself has a strong identity, as the people from the subdivision are not classified as being from Montgomery or Oswego, but instead, Boulder Hill residents generally characterize themselves as being from Boulder Hill.
Postal service is provided to Boulder Hill via the Montgomery Post Office. So while Boulder Hill is unincorporated and not part of the village of Montgomery, there is some confusion because Boulder Hill mailing addresses include "Montgomery" as part of their address simply because their mail goes through that post office. The Village of Montgomery does provide water to the subdivision, but other governmental services provided to Boulder Hill primarily come from either Kendall County or Oswego Township offices.
The community has four churches, a grocery store, a small retail development (Boulder Hill Market), a gas station, three schools (two elementary and a middle school), a retirement facility, and several park district facilities. There's not much vacant land left for development, as the villages of Oswego and Montgomery have both expanded their communities right up to the boundaries of Boulder Hill.
As of the 2000 census, there were 8,169 people, 2,848 households, and 2,229 families residing in Boulder Hill. The average household size was 2.87 and the average family size was 3.25.
Fox Metro: 630-892-4378 for sewer bills and sewer issues
Kendall County Sheriff: 630-553-7500 for police services and neighborhood issues
Kendall County Building & Zoning: 630-553-4141 for building permits and code enforcement issues/complaints
Kendall County Animal Control: 630-553-0256
Kendall County Health Department: 630-553-9100 for health related services, vaccinations, housing assistance, recycling events, and other social services
Montgomery Public Works: 630-896-9241 for water issues
Montgomery Water Billing: 630-896-1357 for water bills
Oswego Township Highway Dept: 630-264-4587 for roadways, sidewalks, leaf and brush pickup, storm water drains, snow plowing and road repairs