Listing provided courtesy of Colorado Realty 4 Less, LLCas Distributed by MLSGrid- MLS# IR1053821MLS Provider

3421 4th StreetBoulder, CO 80304

Single Family · 6 Beds · 2 Full Baths · 1 Half Bath · 2 Three Quarter Baths · 5,198 Sq. ft. | 0.60 Acres
$6,800,000 Active

3421 4th Street Overview

Time on Site:
108 days
Visits:
1

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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3421 4th Street Facts & Features

  • Type Single Family
  • Sq. ft. 5,198
  • Price/Sq.ft. $1,308
  • Lot 0.60 Acres

Details

General

Association/HOA

  • Association: false

School Information

  • School District: Boulder Valley RE 2
  • Elementary School: Foothill
  • Middle Or Junior School: Centennial
  • High School: Boulder

Listing Information

  • Concessions: No

Building Information

  • Year Built: 1990

Location/Region

  • Country: US
  • County Or Parish: Boulder
  • Subdivision Name: Fourth Street 3403 Sub

Tax Information

  • Tax Annual Amount: 26030
  • Tax Year: 2025

General Information

  • Exclusions: Furnishings and Personal Property, Water Rights Included
  • Listing Terms: 1031 Exchange,Cash,Conventional
  • Parcel Number: R0108936
  • Possible Use: Residential
  • Property Sub Type: Single Family Residence
  • Property Type: Residential
  • Zoning: SFR

Interior

Parking Information

  • Garage Spaces: 2

Beds/Baths

  • Bathrooms Full: 2
  • Bathrooms Half: 1
  • Bathrooms Three Quarter: 2
  • Bathrooms Total: 5
  • Bedrooms Total: 6

Building Interior

  • Above Grade Finished Area: 3927
  • Below Grade Finished Area: 1095
  • Building Area Source: Other
  • Building Area Total: 5198

General Information

  • Appliances: Dishwasher,Disposal,Down Draft,Microwave,Oven,Refrigerator,Self Cleaning Oven
  • Cooling: Ceiling Fan(s),Evaporative Cooling
  • Fireplace Features: Family Room,Gas,Gas Log,Living Room
  • Heating: Forced Air,Hot Water,Radiant
  • Interior Features: Eat-in Kitchen,Five Piece Bath,Open Floorplan,Vaulted Ceiling(s),Walk-In Closet(s)
  • Levels: Three Or More
  • Living Area: 5022
  • Main Level Bathrooms: 2
  • Main Level Bedrooms: 1
  • Security Features: Smoke Detector(s)
  • Spa Features: Bath

Exterior

Parking Information

  • Parking Features: Oversized
  • Parking Total: 2

Lot Information

  • Lot Features: Ditch,Open Space,Rolling Slope,Sprinklers In Front
  • Lot Size Acres: 0.6
  • Lot Size Square Feet: 26072
  • Road Surface Type: Paved
  • Vegetation: Wooded
  • Water Source: Public

Waterfront/View

  • View: Mountain(s)

Building Exterior/Construction

  • Architectural Style: Contemporary
  • Attached Garage: true
  • Construction Materials: Frame,Wood Siding
  • Direction Faces: East
  • Patio And Porch Features: Deck,Patio
  • Roof: Composition
  • Structure Type: House

General Information

  • Fencing: Fenced,Partial
  • Road Frontage Type: Public
  • Sewer: Public Sewer
  • Utilities: Cable Available,Electricity Available,Internet Access (Wired),Natural Gas Available

Room Information

Room: Bathroom Full

  • Level: Basement

Room: Bedroom

  • Level: Lower
  • Length: 15
  • Width: 13
  • Description: Carpet

Room: Game Room

  • Level: Lower
  • Length: 14
  • Width: 18
  • Description: Other

Room: Laundry

  • Level: Lower
  • Length: 10
  • Width: 6
  • Description: Other

Room: Bathroom Half

  • Level: Main

Room: Bathroom Three Quarter

  • Level: Main

Room: Bedroom

  • Level: Main
  • Length: 17
  • Width: 23
  • Description: Wood

Room: Dining Room

  • Level: Main
  • Length: 12
  • Width: 13
  • Description: Wood

Room: Great Room

  • Level: Main
  • Length: 14
  • Width: 19
  • Description: Carpet

Room: Kitchen

  • Level: Main
  • Length: 10
  • Width: 15
  • Description: Wood

Room: Living Room

  • Level: Main
  • Length: 13
  • Width: 15
  • Description: Wood

Room: Office

  • Level: Main
  • Length: 11
  • Width: 12
  • Description: Wood

Room: Bathroom Full

  • Level: Upper
  • Features: Primary Suite

Room: Bathroom Three Quarter

  • Level: Upper

Room: Bedroom

  • Level: Upper
  • Length: 11
  • Width: 13
  • Description: Carpet

Room: Bedroom

  • Level: Upper
  • Length: 15
  • Width: 17
  • Description: Carpet
  • Features: Primary Suite

Room: Bedroom

  • Level: Upper
  • Length: 12
  • Width: 12
  • Description: Carpet

Room: Bedroom

  • Level: Upper
  • Length: 11
  • Width: 15
  • Description: Carpet

3421 4th Street Neighborhood

Community

80304 (Boulder) Demographics

41
Median Age
2,891
Population Density (per sq. mile)
81%
College Educated
$98,049
Estimated Median Income
7,931
Estimated Total Home Owners
3,417
Estimated Total Renters
70% / 30%
Estimated Owner / Renter Divide
2
Estimated Average Household Size
Community data courtesy of LiveBy, Inc.

Schools

School data courtesy of LiveBy, Inc. School ratings are based on a scale of 1-5, with 5 being the highest rating and 1 being the lowest rating.

3421 4th Street Monthly Cost

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* All calculations are estimates and provided by Reliance Network, for informational purposes only. Actual amounts may vary. ** Assumes 6.50% APR, 20% down payment, and conventional 30-year fixed rate first mortgage. Rates cited are for instructional purposes only; current rates are subject to change at any time without notice. You should not make any decisions based simply on the information provided. Additional required amounts such as taxes, insurance, homeowner association dues, assessments, mortgage insurance premiums, flood insurance or other such required payments should also be considered. Contact your mortgage company for current rates and additional information. Any mortgage broker or insurance agent that may appear is independent and is not affiliated with, endorsed by, or provided by the MLS.

3421 4th Street Market Data

Based on the last 30 days in this zip code

$2,503,375
Average List Price
$799
Average Price per Square Foot
46
Properties Sold
101
Average Days on Market
233
Properties for Sale
Calculations provided by Reliance Network

3421 4th Street History

Date Event Value Agent
3/13/2026Source: REColorado MLS Added to Database
March 13, 2026