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.
For sale
$6,800,000
3421 4th St, Boulder, CO 80304
6beds
5,198sqft
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
- 112 days |
- 510 |
- 16 |
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#: 1053821
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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
| Date | Event | Price |
|---|---|---|
| 3/13/2026 | Listed for sale | $6,800,000-6.2%$1,308/sqft |
Source:  REcolorado as distributed by MLS GRID #IR1053821 Report a problem | ||
| 12/19/2025 | Listing removed | $7,250,000$1,395/sqft |
Source:  IRES as distributed by MLS GRID #1037712 Report a problem | ||
| 6/26/2025 | Listed for sale | $7,250,000+314.3%$1,395/sqft |
Source: IRES as distributed by MLS GRID #1037712 Report a problem | ||
| 9/16/2004 | Sold | $1,750,000$337/sqft |
Source: Public Record Report a problem | ||
Public tax history
| Year | Property taxes | Tax 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 | -- | $943,300 |
Find assessor info on the county website
Monthly payment
Est. payment$--/mo
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.
Mortgage interest rates are dependent on a number of factors, including credit score, down payment, and repayment length. Interest rate data provided by Zillow Group Marketplace, Inc. as of 1/1/1970 from various mortgage lenders with which we have lead or other similar arrangements; the Estimated Payment is an average of those rates.
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Climate risks
Neighborhood: Juniper - Kalmia
Nearby schools
GreatSchools rating
- 8/10Foothill Elementary SchoolGrades: K-5Distance: 0.5 mi
- 7/10Centennial Middle SchoolGrades: 6-8Distance: 1.4 mi
- 10/10Boulder High SchoolGrades: 9-12Distance: 1.9 mi
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.
A local agent can set up tours, give advice and negotiate with sellers.
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