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For sale
    • $6,800,000

    3421 4th St, Boulder, CO 80304

    6beds
    5,198sqft
    : 
    $38,640/mo
    Get pre-qualified
    Single Family Residence
    Built in 1990
    0.6 Acres Lot
    $-- Zestimate®
    $1,308/sqft
    $-- HOA

    What's special

    Two fireplacesFlower and vegetable gardensSix bedrooms plus officeWhite oak floorsDedicated office
    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.
    158 days
    |
    600
    |
    15
    |

    Zillow last checked:

    Listing updated:

    Listed by:

    Kathleen Haas 970-531-7448,

    Colorado Realty 4 Less, LLC

    Source: IRES as distributed by MLS GRID,MLS#: 1053821MLS Logo

      Facts & features

      Interior

      Bedrooms & bathrooms
      • Bedrooms: 6
      • Bathrooms: 5
      • Full bathrooms: 2
      • 3/4 bathrooms: 2
      • 1/2 bathrooms: 1
      • Main level bathrooms: 2
      Primary bedroom
      • Description: Carpet
      • Features: Full Primary Bath, Tub+Shower Primary, Luxury Features Primary Bath, 5 Piece Primary Bath
      • Level: Upper
      • Area: 255 Square Feet
      • Dimensions: 17 x 15
      Bedroom 2
      • Description: Carpet
      • Level: Upper
      • Area: 144 Square Feet
      • Dimensions: 12 x 12
      Bedroom 3
      • Description: Carpet
      • Level: Upper
      • Area: 143 Square Feet
      • Dimensions: 13 x 11
      Bedroom 4
      • Description: Carpet
      • Level: Upper
      • Area: 165 Square Feet
      • Dimensions: 15 x 11
      Bedroom 5
      • Description: Wood
      • Level: Main
      • Area: 391 Square Feet
      • Dimensions: 23 x 17
      Bedroom 6
      • Description: Carpet
      • Level: Lower
      • Area: 195 Square Feet
      • Dimensions: 13 x 15
      Dining room
      • Description: Wood
      • Level: Main
      • Area: 156 Square Feet
      • Dimensions: 13 x 12
      Great room
      • Description: Carpet
      • Level: Main
      • Area: 266 Square Feet
      • Dimensions: 19 x 14
      Kitchen
      • Description: Wood
      • Level: Main
      • Area: 150 Square Feet
      • Dimensions: 15 x 10
      Laundry
      • Description: Other
      • Level: Lower
      • Area: 60 Square Feet
      • Dimensions: 6 x 10
      Living room
      • Description: Wood
      • Level: Main
      • Area: 195 Square Feet
      • Dimensions: 15 x 13
      Recreation room
      • Description: Other
      • Level: Lower
      • Area: 252 Square Feet
      • Dimensions: 18 x 14
      Study
      • Description: Wood
      • Level: Main
      • Area: 132 Square Feet
      • Dimensions: 12 x 11
      Heating
      • Forced Air, Hot Water, Zoned, Radiant, 2 or more Heat Sources
      Cooling
      • Evaporative Cooling, Ceiling Fan(s)
      Appliances
      • Included: Gas Range, Down Draft, Self Cleaning Oven, Dishwasher, Refrigerator, Microwave, Disposal
      Features
      • Eat-in Kitchen, Separate Dining Room, Cathedral Ceiling(s), Open Floorplan, Walk-In Closet(s)
      • Basement: Full,Partially Finished,Daylight
      • Has fireplace: Yes
      • Fireplace features: Two or More, Gas, Gas Log, Living Room, Family Room
      Interior area
      • Total structure area: 3,927
      • Total interior livable area: 5,198 sqft
      • Finished area above ground: 3,927

      Property

      Parking
      • Total spaces: 2
      • Parking features: Garage Door Opener, Attached, Oversized
      • Attached garage spaces: 2
      • Details: Attached
      Features
      • Levels: Four
      • Stories: 4
      • Patio & porch: Patio, Deck
      • Exterior features: Sprinkler System
      • Spa features: Bath
      • Fencing: Partial,Fenced,Wood,Chain Link
      • Has view: Yes
      • View description: Hills
      Lot
      • Size: 0.6 Acres
      • Features: Wooded, Evergreen Trees, Deciduous Trees, Sloped, Abuts Ditch, Abuts Public Open Space, Paved, Water Rights Included
      Details
      • Parcel number: R0108936
      • Zoning: SFR
      • Special conditions: Other Owner

      Construction

      Type & style
      • Home type: SingleFamily
      • Architectural style: Legal Conforming,Contemporary
      • Property subtype: Single Family Residence
      Materials
      • Frame, Wood Siding
      • Roof: Composition
      Condition
      • New construction: No
      • Year built: 1990

      Utilities & green energy

      • Electric: Xcel
      • Gas: Xcel
      • Sewer: Public Sewer
      • Water: City
      • Utilities for property: Natural Gas Available, Electricity Available, Cable Available, High Speed Avail

      Community & HOA

      Community
      • Security: Fire Alarm
      • Subdivision: Fourth Street 3403 Sub
      HOA
      • Has HOA: No
      Location
      • Region: Boulder

      Financial & listing details

      • Price per square foot: $1,308/sqft
      • Tax assessed value: $4,367,900
      • Annual tax amount: $26,030
      • Date on market: 3/13/2026
      • Listing terms: Cash,Conventional,1031 Exchange
      • Exclusions: Furnishings and Personal Property
      • Electric utility on property: Yes
      • Road surface type: Asphalt

        Estimated market value

        Not available

        Estimated sales range

        Not available

        Not available

        Price history

        DateEventPrice
        3/13/2026Listed for sale$6,800,000-6.2%$1,308/sqft
        Source: REcolorado as distributed by MLS GRID #IR1053821 Report a problem
        12/19/2025Listing removed$7,250,000$1,395/sqft
        Source: IRES as distributed by MLS GRID #1037712 Report a problem
        6/26/2025Listed for sale$7,250,000+314.3%$1,395/sqft
        Source: IRES as distributed by MLS GRID #1037712 Report a problem
        9/16/2004Sold$1,750,000$337/sqft
        Source: Public Record Report a problem

        Public tax history

        YearProperty taxesTax assessment
        2025$26,869 +1.8%$272,994 -11.8%
        2024$26,402 +14.3%$309,412 -1%
        2023$23,101 +4.9%$312,415 +25.6%
        2022$22,028 +27.1%$248,761 -2.8%
        2021$17,338 $255,920 +28.5%
        2020$17,338 +8.8%$199,185
        2019$15,932 $199,185 +8.4%
        2018$15,932 $183,758 -9.5%
        2017$15,932 +13.1%$203,155 +24.8%
        2016$14,091 +5.6%$162,774 +44.6%
        2015$13,343 +40.9%$112,602
        2014$9,468 +3%$112,602
        2013$9,189 +0.9%$112,602 +2.7%
        2012$9,108 -27%$109,689
        2011$12,471 +7.1%--
        2010$11,645 +22.2%$154,300
        2009$9,530 +3.5%$154,300 +3.6%
        2008$9,205 +3%$148,940
        2007$8,937 +9.3%$148,940 +12.1%
        2006$8,177 +28.3%$132,900
        2005$6,373 +0.7%$132,900 +27.4%
        2004$6,328 +5.1%$104,310
        2003$6,023 +10.3%$104,310 +20.9%
        2002$5,459 $86,310 -90.9%
        2001-- $943,300
        Find assessor info on the county website

        Monthly payment

        Est. payment

        Payment breakdown

        Explore the cost of this home by adjusting the details. Changes won't be saved.
        All calculations are estimates and provided by Zillow, Inc. for informational purposes only. Actual amounts may vary.
        HOA fees may include property taxes on listings classified as Co-Ops. Contact the listing agent and/or owner for fee details.
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        Climate risks

        Neighborhood: Juniper - Kalmia

        Getting around

        9 / 100
        Car-Dependent
        33 / 100
        Some Transit
        50 / 100
        Bikeable

        Nearby schools

        GreatSchools rating
        Schools provided by the listing agent
        • Elementary: Foothill
        • Middle: Centennial
        • High: Boulder

        Source: IRES as distributed by MLS GRID. This data may not be complete. We recommend contacting the local school district to confirm school assignments for this home.

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