3421 4th Street Boulder, CO ^$ 6,800,000

3421 4th Street

^$ 6,800,000

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3421 4th Street

Boulder, CO, 80304

^$ 6,800,000

Bedrooms6 Baths4.1 Sq 5,198

Monthly Estimate*

^$ 41,869

Listed by Colorado Realty 4 Less, LLC

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Single Family Home for sale in Boulder, CO

for $6,800,000 with 6 bedrooms and 4 full baths, 1 half bath. This 5,198 square foot home was built in 1990 on a lot size of 0.6.

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.

Single Family Active

Price

^$ 6,800,000

Bedrooms

Full Bath

Half Bath

Property Type

Single Family

Taxes

^$ 26,030

Style

Contemporary

Lot Size

0.6

Year Built

1990

Town/City

Boulder

County/Region

Boulder

MLS | Web ID

IR1053821

Features

Interior

Interior Amenities Eat-in Kitchen Five Piece Bath Open Floorplan Vaulted Ceiling(s) Walk-In Closet(s)

Basement Daylight Full

Fireplace Features Family Room Gas Gas Log Living Room

Basement (Y/N) Y

Above Grade Finished Area 3927

Half Baths 1

3/4 Baths 2

Total Bedrooms 6

Below Grade Finished Area 1095

Main Level Bedrooms 1

Main Level Bathrooms 2

Total Baths 5

General

Sewer Public Sewer

Heating Forced Air Hot Water Radiant

Cooling Ceiling Fan(s) Evaporative Cooling

Utilities Cable Available Electricity Available Internet Access (Wired) Natural Gas Available

Possession Closing/DOD

Roof Composition

Appliances Dishwasher Disposal Down Draft Microwave Oven Refrigerator Self Cleaning Oven

Zoning SFR

Garage Spaces 2

Patio/Porch Features Deck Patio

Architectural Style Contemporary

Security Features Smoke Detector(s)

Construction Materials Frame Wood Siding

Exclusions Furnishings and Personal Property Water Rights Included

Year Built 1990

View Mountain(s)

Levels Three Or More

Property Subtype Single Family Residence

Tax Year 2025

County Boulder

Property Type Residential

HOA N

Attached Garage Y

Subdivision Name Fourth Street 3403 Sub

Facing Direction East

Possible Use Residential

Full Baths 2

Status Active

Directions From Broadway turn left on Juniper Ave. Turn right on 4th St. Property on left side.

High School Boulder

City Boulder

High School District Boulder Valley RE 2

Lot Size Square Feet 26072

Listing Terms 1031 Exchange Cash Conventional

Spa Features Bath

Elementary School Foothill

Tax Annual Amount 26030

Middle/Junior High School Centennial

Concessions No

Structure Type House

Standard Status Active

Occupancy Type Owner

Elementary School District Boulder Valley RE 2

Exterior

Vegetation Wooded

Fencing Fenced Partial

Parking Features Oversized

Lot Features Ditch Open Space Rolling Slope Sprinklers In Front

Water Source Public

Total Parking 2

Building Area Total 5198

Lot Size Acres 0.6

Road Surface Type Paved

Road Frontage Type Public

Internal Only

Street Number 1 3421

* Excluded Features

List By

Colorado Realty 4 Less, Llc

Broker

(970) 531-7448

Phone

Affordability Calculator

$44,038

Per Month

Monthly Principal & Interest: $41,869
Monthly Property Taxes: $2,169
Monthly Home Insurance: --

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Down Payment

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Yearly Home Insurance

Default based on a 30-year fixed rate of 6.25% with 20% down. The estimated payment is offered for convenience and is not an offer of credit. Due to market fluctuations, interest rates are subject to change at any time and without notice. Your individual rate may vary. Rates may differ for FHA, VA or jumbo loans.

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Nearby

Trends
Schools

Single family listings in Boulder, CO

Average List Price ^$2,600,010

Percent of Sale Price 62%

About Boulder, CO

102,151 Population

6% Since 2002

^$65,436 Median Income

31.88 Median Age

18% Households with Children

View more area information

Trends Information provided by ATTOM Data Solutions.

1955676 Elementary School

1955871 Middle School

Boulder High School High School

See complete school information

Pricing History

Date	Price	Price Change	Description
3/13/2026	$6,800,000		Listed Price

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3421 4th Street, Boulder, CO, 80304 is a Single Family Home for sale at $6,800,000 with 5,198 sqft and a lot size of 0.6. 3421 4th Street has 6 bedrooms, 4.1 baths, and was built in 1990. The property's zip code is 80304 which is in Boulder, CO

*Information deemed reliable but not guaranteed.

Financial calculator disclaimer: Default based on a 30-year fixed rate of 6.25% with 20% down. The estimated payment is offered for convenience and is not an offer of credit. Due to market fluctuations, interest rates are subject to change at any time and without notice. Your individual rate may vary. Rates may differ for FHA, VA or jumbo loans.

The data relating to real estate on this web site comes in part from the Internet Data eXchange (IDX) Program of the REcolorado. Real estate listings held by firms other than Weichert Realtors are marked with the IDX logo and detailed information about them includes the Listing Broker’s Firm Name.

The information being provided is for consumers personal, non-commercial use and may not be used for any purpose other than to identify prospective properties consumers may be interested in purchasing.

Data is updated as of 3/25/2026.

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3421 4th Street

Single Family Home for sale in Boulder, CO

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