Property
ActiveResidential
Sun Jul 5, 12:00PM-4:00PM
1/40
$6,800,000

3421 4th Street

Boulder, CO 80304
6
Beds
5
Baths
5,198
SqFt
0.6
Acres
RECOLORADO
#IR1053821
Updated: Jun 30, 2026, 10:45am

Property Description

Newlands Sanctuary on Mt. Sanitas Open Space Step onto the 600-square-foot deck and look up. Mt. Sanitas rises 1,300 feet from your backyard gate, private access to the Goat Trail. No driving. No parking. Just you, your coffee, and maybe a 4-legged friend who will make sure you don't skip it. This premier property is one of eight homes backing directly to open space. In 21 years, only one has changed hands. Hidden behind a 70-yard tree-lined driveway on a 0.6-acre lot (2.5x standard), this is widely regarded as one of Boulder's best addresses, served by top rated schools.The 5,200-square-foot residence features 20-foot ceilings with west-facing glass framing Mt. Sanitas, white oak floors, two fireplaces, and a library overlooking the property's seven heritage apple trees. Six bedrooms plus office (convertible seventh) include three distinct suites: the primary en-suite with a stunning view; a garden-level walkout in-law addition (2005, 12' ceilings) with separate entrance, private patio, and dedicated office-ideal for multigenerational living or guests-plus a basement suite with whirlpool bath. Outside you will discover a deep wrap-around porch beneath a 60-foot silver maple, flower and vegetable gardens, and the historic Silver Lake Ditch with 12,000 gallons daily water rights. Sundance Film Festival arrives January 2027, venues minutes away providing a chance at an incredible rental income opportunity and under the Augusta Rule, 14 days of rental income may be tax-free. Roof replaced 2019. New carpet. Heated two-car garage. No HOA. No covenants. For those who know Newlands: this is the privacy, the lot, the view, and the trail access that almost never comes to market. For those discovering Boulder for the first time: welcome to the neighborhood the locals covet most.
Included Appliances
DishwasherDisposalDown DraftMicrowaveOvenRefrigeratorSelf Cleaning Oven

Property Details

Interior
Above Grade Finished Area
3927
Appliances
DishwasherDisposalDown DraftMicrowaveOvenRefrigeratorSelf Cleaning Oven
Basement
DaylightFull
Below Grade Finished Area
1095
Below Grade Unfinished Area
176
Building Area Total
5198
Cooling
Ceiling Fan(s)Evaporative Cooling
Fireplace Features
Family RoomGasGas LogLiving Room
H V A C Description
Evaporative Cooler,Ceilin
Heating
Forced AirHot WaterRadiant
Interior Features
Eat-in KitchenFive Piece BathOpen FloorplanVaulted Ceiling(s)Walk-In Closet(s)
Living Area
5022
Room Count
18
Security Features
Smoke Detector(s)
Construction
Architectural Style
Contemporary
Building Area Source
Other
Construction Materials
FrameWood Siding
Direction Faces
East
Levels
Three Or More
Roof
Composition
Structure Type
House
Year Built
1990
Site & Exterior
Fencing
FencedPartial
Garage Spaces
2
Lot Features
DitchOpen SpaceRolling SlopeSprinklers In Front
Lot Size Acres
0.6
Lot Size Square Feet
26072
Parking Features
Oversized
Parking Total
2
Patio And Porch Features
DeckPatio
Road Frontage Type
Public
Road Surface Type
Paved
Sewer
Public Sewer
Spa Features
Bath
Utilities
Cable AvailableElectricity AvailableInternet Access (Wired)Natural Gas Available
Vegetation
Wooded
View
Mountain(s)
Water Mineral Rights
Water Rights
Water Source
Public
Zoning
SFR
Financials
Contract Earnest Check To
Land Title
Contract Min Earnest
125000.00
Exclusions
Furnishings and Personal PropertyWater Rights Included
Parcel Number
R0108936
Tax Annual Amount
26030
Tax Legal Description
LOT 2 & NWLY TRI LOT 1 3403 FOURTH STREET
Tax Year
2025

Neighborhood & Lifestyle

Community & Association
Subdivision Name
Fourth Street 3403 Sub
Schools
Ratings
Elementary
Foothill
Middle
Centennial
High
Boulder
Elem. District
Boulder Valley RE 2
High District
Boulder Valley RE 2
Listing provided courtesy of RECOLORADO via IDX. Updated: Jun 30, 2026, 10:45am.
Kathleen Haas

Listing Agent

Colorado Realty 4 Less, LLC

Call Agent