In the State of Colorado, an Improvement Location Certificate (ILC) is a map prepared by a licensed land surveyor to show the visible improvements on a particular parcel of land. An ILC is typically used in real estate transactions to allow Title Companies, Lenders, and Municipalities to verify what has been built on a parcel of land. An ILC usually shows the position of a house, driveway, and visible utilities as they relate to the parcel’s boundary.