Boulder County brings two very different Colorado landscapes into one map. Boulder, Longmont, Lafayette, Louisville, and other Front Range communities occupy the lower eastern side, while Nederland, Ward, Jamestown, and Allenspark sit among much steeper mountain terrain to the west. The supplied reference, city, water, and elevation views make that contrast easy to follow, and high-resolution JPG originals are available for download in one ZIP archive.
The main reference map is built around Boulder and Longmont as the strongest eastern anchors. US 36 links the urban corridor, US 287 runs through the plains farther east, and routes such as CO 119, CO 72, CO 7, and CO 93 lead toward the foothills and mountain communities. The road pattern changes quickly from a connected urban network in the east to winding valley routes in the west.
Water and elevation reinforce the same east-west divide. North St. Vrain Creek, South St. Vrain Creek, Left Hand Creek, and South Boulder Creek descend from the mountains toward the plains, while Boulder Reservoir and several smaller reservoirs sit closer to the developed east. The elevation map spans roughly 1,491 to 4,340 meters, showing how rapidly Boulder County rises from the Front Range communities into the high Rockies.
Table of Contents
Front Range cities on the east, mountain communities on the west
The eastern half of Boulder County contains the densest group of cities and roads. Boulder sits close to the foothills, Longmont occupies a broader plain to the northeast, and Lafayette, Louisville, and Superior cluster near the southeastern edge. Gunbarrel is also labeled between Boulder and Longmont, while Erie and Broomfield appear just outside or along the county’s eastern and southeastern context.
West of the foothills, the map changes character quickly. Nederland and Ward lie deeper in the mountains, Jamestown occupies a smaller valley setting, and Allenspark appears near the northwestern side. Roads are fewer and more curved because they follow canyons and mountain terrain rather than a broad street grid. That difference is one of the most useful things to notice before looking at the individual map layers.
Boulder County’s official incorporated-municipalities page lists ten towns and cities, including Boulder, Longmont, Lafayette, Louisville, Lyons, Nederland, Superior, Ward, and Jamestown. The city-distribution map on this page highlights only six major places, so it should not be interpreted as a complete list of every incorporated municipality or community in the county.
US 36, CO 119, and the road transition into the mountains
US 36 is one of the clearest road references on the main county map, connecting the Boulder area with Longmont and the broader Front Range corridor. US 287 runs north-south farther east, while CO 52 provides another east-west connection across the plains. From Boulder, CO 119 heads into the mountains toward Nederland, and CO 93 continues south along the foothills.
North of Boulder, CO 7 reaches Lyons and continues toward mountain terrain, while CO 66 crosses the plains east of Lyons. Nederland is connected with CO 72 as well as CO 119, and roads near Ward and Allenspark become more limited as elevation rises. Reading the large route numbers first makes it easier to understand how the urban east connects with the mountain west.
This reference map is useful for county orientation, reports, lessons, and broad route context. It is not a live navigation product and does not show current closures, winter road conditions, or private access restrictions. The county outline is also not a parcel survey; exact legal or property boundaries require current county records or authoritative boundary data.
Six major cities concentrated along the lower eastern side
The city-distribution map highlights Boulder, Longmont, Lafayette, Louisville, Superior, and Lyons. Boulder is ranked first in the map’s city index and Longmont second, while Lafayette, Louisville, and Superior form a tight southeastern group. Lyons sits farther northwest near the transition from the plains into the foothills.
The distribution makes the eastern concentration of population easy to see even without detailed road labels. Boulder lies immediately against the foothills, Longmont spreads across the northeastern plain, and the three southeastern cities sit close to one another near the county boundary. Lyons is separated from that cluster and works well as a northern foothill reference point.
The CITY INDEX values belong to the map’s ranking display and should not automatically be treated as current Census population figures. Current demographic numbers should come from a recent Census release. The county’s official municipality page also includes places not highlighted in this six-city view, such as Nederland, Ward, and Jamestown.
St. Vrain creeks, Boulder Reservoir, and mountain water sources
The terrain-and-water map shows how streams descend from the high western half toward the plains. North St. Vrain Creek and South St. Vrain Creek cross the northern mountains, Left Hand Creek drains the central foothills, and South Boulder Creek runs through the southern part of the county. Coal Creek and Dry Creek appear farther east and southeast as the terrain becomes lower and more open.
Several reservoirs and lakes are named on the map. Boulder Reservoir, Valmont Reservoir, Baseline Reservoir, McIntosh Lake, Terry Lake, and Ish Reservoir lie on or near the lower eastern side, while Gross Reservoir sits much farther southwest inside mountain terrain. Marshall Lake is also labeled near the southeastern part of the county.
The City of Boulder describes Boulder Reservoir as a multi-use recreation and water-storage facility. On the county map it stands out as a large water body on the plains, in sharp contrast with Gross Reservoir’s location among steep ridges and valleys. Comparing those two reservoirs is a simple way to see how different the county’s eastern and western landscapes are.
This map is designed for general water-feature location, not flood forecasting, reservoir operations, drinking-water decisions, water rights, or navigation. Those uses require current information from Boulder County, the City of Boulder, USGS, or the relevant water-management agency.
A rapid rise from the eastern plains into the high Rockies
The elevation map gives the clearest single view of Boulder County’s east-west contrast. Its printed summary shows an actual range of about 1,491 to 4,340 meters, with a mean near 2,255 meters. Low green terrain covers much of the eastern side, then shifts through lighter green and yellow into brown high country along the western boundary.
Boulder and Longmont occupy the lower side of that gradient, while the ground rises rapidly just west of Boulder into deeply cut foothills and mountain valleys. Nederland and Ward lie much higher, and the western edge contains the darkest high-elevation colors. Comparing the elevation and water maps also shows why St. Vrain, Left Hand, and Boulder-area creeks generally descend toward the lower eastern side.
The colored surface is useful for comparing broad terrain, but it is not survey-grade elevation information. It should not be used to assign an exact height to a house, road project, trail structure, or parcel. Detailed engineering or site work should use source elevation data from the USGS 3D Elevation Program or a professional survey.
Choosing a Boulder County map and downloading the high-resolution files
Start with the main reference map when you need Boulder, Longmont, Nederland, Lyons, major highways, and county boundaries in one view. The city map is cleaner when the goal is simply to compare the six highlighted urban locations. For North and South St. Vrain Creek, Left Hand Creek, Boulder Reservoir, Gross Reservoir, and other water features, the terrain-and-water map provides the clearest labels.
The elevation map is the best choice when the subject is the rapid climb from the Front Range plains into the Rockies. It makes the eastern urban corridor and western high country easy to compare without adding road or city labels. Selecting the map that matches the question usually communicates Boulder County more clearly than stacking every layer into one image.
The WebP images in the article are reduced for faster page loading. The download archive contains the corresponding original JPG files at 3638 × 2572 pixels each, making them better suited to printing, presentations, classroom use, reports, and personal annotation.
Frequently Asked Questions
Which map is best for comparing Boulder, Longmont, and Nederland?
Use the main county reference map. It places the eastern cities and mountain communities in the same frame and includes US 36, CO 119, CO 72, and other major roads, making the plains-to-mountains relationship easy to follow.
Where can I see St. Vrain Creek and Boulder Reservoir most clearly?
The terrain-and-water map is the best choice. It labels North and South St. Vrain Creek, Left Hand Creek, South Boulder Creek, Boulder Reservoir, Gross Reservoir, and several smaller reservoirs and lakes. It is a location reference rather than a flood or real-time water map.
Can the 1,491–4,340 meter elevation range be used for survey work?
No. The range is useful for comparing broad terrain across Boulder County, but the map is not survey-grade. Exact elevation work for construction, roads, parcels, or engineering should use source USGS elevation data or professional surveying.
Map File Information
The ZIP archive contains high-resolution JPG originals of the Boulder County reference, city, terrain-and-water, and elevation maps.
- Printable Size: 3638 × 2572 pixels each
- File Type: ZIP archive containing the original JPG files
Related Maps
Sources and references
Local municipality information is available from the Boulder County Incorporated Municipalities page. County parks and open-space geography can be explored through Boulder County Open Space Maps, and the City of Boulder Boulder Reservoir page provides official information about that reservoir.
Additional map-data references include U.S. Census Bureau TIGER/Line Shapefiles for administrative boundaries, USGS National Hydrography for water features, and the USGS 3D Elevation Program for elevation data.
Green Map creates custom-edited map images using open geographic data sources such as geoBoundaries, Natural Earth, OpenStreetMap, and government open data.
These maps are edited visual materials, not raw data files, and are provided for education, documents, presentations, and graphic reference.
