About Us

Lake County Geographic information System (GIS) Division is a service driven resource providing support for the coordination and development of an enterprise GIS for the benefit of all Lake County departments and its residents.

Thank you for visiting the Lake County Geographic Information System (GIS) Division web pages. The GIS Division is part of Lake County's Chief County Assessment Office. We have developed an interactive web site Maps Online for public access which lets residents and businesses use GIS tools to explore, answer questions and make maps on the Internet. Additionally, we publish approximately 1,300 tax district boundary maps which may be found in our Open Data Portal. We also support and coordinate the development of GIS computer applications in county agencies and work with almost 150 federal, state, regional and local government agencies and non-profit organizations to promote the growth of GIS and its use to benefit residents in our area.

Our office also offers a number of digital data products for free download, including aerial photography, contour data and numerous other GIS themes available using our Open Data Portal.

History of GIS in Lake County

Lake County started a mapping program in 1941. The newly created Map Department was responsible for providing tax parcel and tax district maps and for the maintenance of a systematic series of card files with property ownership records for use by county departments and the public. In 1981 the Map Department became a division of what is now the Department of Information Technology and was renamed the Map Division. An interdepartmental study group was then formed to explore the benefits and implementation of a countywide GIS. A vision of a multi-application, multi-agency, broadly based program that would support many county projects and operations was developed. The Map Division was renamed to the GIS/Mapping Division with the assignment of implementing this new vision. In 2015 the tax parcel and tax district mapping function and related staff was transferred to the Chief County Assessor’s Office, then in 2020 the GIS function was also transferred to that office.

In the 30 plus years since its creation, a fully mature, well respected and effective GIS has been developed. The Division now handles a far larger workload with fewer staff than it did 30 years ago. In addition to the annual publication of over 1,300 maps, the GIS Division also coordinates, develops informative applications and provides training and support for the countywide GIS which directly benefits the public and many other local, state and federal government agencies. During the economic downturn starting in 2008, our customers increasingly relied on geospatial analysis and services to help efficiently enhance and extend their business operations. This reliance underlines the value an established GIS, along with seasoned professional staff, affords Lake County and its residents.


Tax System and Land Records

  • Assign addresses in unincorporated Lake County and by those municipalities that request this service
  • Ensure accurate, complete and timely entry of a significant portion of the County’s tax system
  • Consolidate and divide tax parcels on request for tax assessment and billing purposes
  • Initial assignment of Permanent Index Numbers (PIN) to tax parcels
  • Subdivide and consolidate tax parcels pursuant to deeds, subdivision plats and other legal documents
  • Maintain and publish tax parcel maps and tax district maps

Customer Service

  • Provide a high level of service to both internal and public customers
  • Provide assistance to the public in using, interpreting and understanding GIS web applications, maps and GIS data products
  • Provide technical assistance to departments that empowers them to leverage the benefits of GIS to support their individual business requirements
  • Provide coordination so that all County desktop GIS users create compatible data that integrates with the County program
  • Publish GIS web applications, maps and other GIS data on the Internet
  • Support County programs (Emergency Operations Center; Sheriff’s Dispatch Center, COVID-19 response, etc.)

GIS System Management

  • Develop hardware plans to address capacity and performance needs
  • Provide guidance to client agencies for GIS-related hardware specifications
  • Test and evaluate new releases of GIS software and coordinate installation and implementation
  • Monitor the performance of enterprise GIS resources
  • Develop strategic plan for enterprise GIS resources

GIS Data Development

  • Acquire or develop and maintain data layers needed for County applications but not the responsibility of any existing County department
    • Aerial photography
    • Natural Resources – State Parks, open space, nature preserves, etc.
    • Planimetrics – Pavement, building footprints, etc.
    • Soils
    • Street centerlines, trails, address points
  • Assist with the acquisition or development of data layers needed by County applications but maintained by other departments
    • Drainage Resources - FEMA, field tiles, watersheds, etc.
    • Topography – LiDAR, contours, surface models
    • Wetlands, water bodies, etc.

GIS Applications

  • That are easy to use and intuitive
  • That primarily leverage COTS solutions
  • That are cost effective both to develop and maintain
  • That are secure
  • That are up-to-date
  • That provide meaningful information that help users make informed decisions

Cooperative Opportunities

  • Work cooperatively with outside agencies, creating data sharing and other partnership arrangements for mutual benefit
  • Seek opportunities to promote/support studies and projects done by other agencies that benefit Lake County
  • Work cooperatively with neighboring counties to develop common standards for data we share with each other and with other agencies
  • Integrate spatial data from participating counties in Northeastern Illinois so it fits together precisely and carries core attributes that follow a common standard
  • Explore cooperative data development opportunities with other agencies, like regional aerial photography, LiDAR data, planimetrics, etc.