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$6,800,000
1 Day On Site

3421 4th Street
Boulder, CO 80304

For Sale|Single Family Residence|Active
6
Beds
5
Total Baths
2
Full Baths
3
Partial Baths
5,022
SqFt
$1,354
/SqFt
1990
Built
Subdivision:
Fourth Street 3403 Sub
County:
Boulder
3421 4th Street3421 4th Street3421 4th Street3421 4th Street
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Monthly Payment (Est.)

$31,024
Calculator powered by Showcase IDX, a Constellation1 Company. Copyright ©2026 Information is deemed reliable but not guaranteed.

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.

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Listing Snapshot
Price 
$6,800,000
Days On Site 
1 Day
Bedrooms 
6
Inside Area (SqFt) 
5,022 sqft
Total Baths 
5
Full Baths 
2
Partial Baths 
3
Lot Size 
0.6 Acres
Year Built 
1990
MLS® Number 
IR1053821
Status 
Active
Property Tax 
$26,030
HOA/Condo/Coop Fees 
N/A
Sq Ft Source 
Other
Friends & Family
Recent Activity
15 hours agoListing updated with changes from the MLS®
yesterdayListing first seen on site
General Features
Acres 
0.6
Additional Property Use 
Residential
Attached Garage 
Yes
Direction Faces 
East
Garage 
Yes
Garage Spaces 
2
Levels 
Three Or More
Parking 
OversizedAttached
Parking Spaces 
2
Property Sub Type 
Single Family Residence
Security 
Smoke Detector(s)
Sewer 
Public Sewer
SqFt Above 
3927
SqFt Below 
1095
SqFt Total 
5198
Style 
Contemporary
Utilities 
Cable AvailableElectricity AvailableNatural Gas Available
Water Source 
Public
Zoning 
SFR
Interior Features
Appliances 
OvenDishwasherDisposalDown DraftMicrowaveRefrigeratorSelf Cleaning Oven
Basement 
DaylightFull
Cooling 
Ceiling Fan(s)Evaporative Cooling
Fireplace Features 
Family RoomGasGas LogLiving Room
Heating 
Forced AirHot WaterRadiant
Interior 
Eat-in KitchenOpen FloorplanVaulted Ceiling(s)Walk-In Closet(s)
Main Level Bedrooms 
1
Bathroom Full 
Level - Basement
Bathroom Half 
Level - Main
Bathroom Three Quarter 
Level - Main
Bedroom 
Dimensions - 11 x 13Level - UpperDescription - Carpet
Dining Room 
Dimensions - 12 x 13Level - MainDescription - Wood
Game Room 
Dimensions - 14 x 18Level - LowerDescription - Other
Great Room 
Dimensions - 14 x 19Level - MainDescription - Carpet
Kitchen 
Dimensions - 10 x 15Level - MainDescription - Wood
Laundry 
Dimensions - 10 x 6Level - LowerDescription - Other
Living Room 
Dimensions - 13 x 15Level - MainDescription - Wood
Office 
Dimensions - 11 x 12Level - MainDescription - Wood
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Exterior Features
Construction Details 
FrameWood Siding
Fencing 
FencedPartial
Lot Features 
SlopedWoodedRolling SlopeSprinklers In Front
Patio And Porch 
DeckPatio
Roof 
Composition
Spa Features 
Bath
View 
Mountain(s)
Waterview 
Mountain(s)
Community Features
Financing Terms Available 
1031 ExchangeCashConventional
Roads 
Paved
School District 
Boulder Valley RE 2
Schools
School District
Boulder Valley RE 2
Elementary School
Foothill
Middle School
Centennial
High School
Boulder
Listing courtesy of Colorado Realty 4 Less, LLC KathyHaas@ColoradoRealty4Less.com



The content relating to real estate for sale in this Web site comes in part from the Internet Data eXchange ("IDX") program of METROLIST, INC., DBA RECOLORADO real estate listings held by brokers other than Colorado Realty 4 Less, LLC are marked with the IDX Logo. This information is being provided for the consumers' personal, non-commercial use and may not be used for any other purpose. All information subject to change and should be independently verified.

Neighborhood & Commute
Source: Walkscore
Disclosure: Community information and market data powered by Constellation Data Labs. Information is deemed reliable but not guaranteed.
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