The Boulder County Road Map is the single official record of ownership, use, and maintenance of the county roadway network. The Road Map consists of two parts:
- The Road Map – Shows the location, ownership, functional class, and alignment of each Road; and,
- The Road Directory – Lists detailed information about each road segment.
Road maps for each county in the state are required by Colorado Revised Statute (CRS) 43-2-110. At its inception, the Road Map provided a geographic record of the primary and secondary road systems, including an official record of the location and type of roadways throughout Boulder County.
Since the Road Map’s initial publication in 1954, the Public Works Department has continued to reconcile both the Map and the Directory with official documentation of road status, ownership, and classification, as well as field-researched dimensions.
The latest Road Map is up for approval/acceptance by the Board of County Commissioners on Sept. 4, 2025 and serves as the current record of Boulder County roads.
- Official Boulder County Road Map (current) – This is a large file that may take a few moments to open.
- Interactive Boulder County Road Web Map
Official County Roadway Classifications and Maintenance Descriptions
The Road Directory on the back of the Road Map shows a list of all county-owned roads. Next to each roadway name is its location, surface type (gravel or paved), classification (info below), and official length. Functional classifications** and maintenance descriptions are as follows:
- PA – Principal Arterial – The road will be maintained to provide for continuous access within the maximum capabilities of the county
- MA – Minor Arterial – The road will be maintained to provide for continuous access within the maximum capabilities of the county
- C – Collector – The road will be maintained to provide continuous access as time, available funds, and manpower permit
- RC – Residential Collector – The road will be maintained to provide continuous access as time, available funds, and manpower permit
- L – Local – The road will be maintained to provide reasonable access as time, available funds, and manpower permit
- LS – Local (Secondary) – The road will be maintained to provide reasonable access as time, available funds, and manpower permit. Maintenance of these roads may be for seasonal use and winter access may be restricted.
- J – Jeep – The road is not maintained for access by passenger cars. Four-wheel drive or high-clearance vehicles are recommended on these roads.
**Functional Classifications are explained in more detail within Boulder County’s Multimodal Transportation Standards.