See Home Value
$10,000,000
● House - Off Market

3633 21st St

Boulder, CO 80304
bedrooms
7 Beds
bathrooms
3 Baths, 1 Half Bath
square feet
6,988 Ft²
$51,572
Est. Monthly

About This Property

Exquisite secluded sanctuary in the heart of Carolyn Heights. Tucked into one of Boulder's most prestigious enclaves, this estate offers a rare fusion of luxury, privacy, and relaxed sophistication. Set on a serene, tree-lined .81-acre level lot, this 7-bedroom, 5-bathroom oasis is where inspired design meets effortless living. Stunning views of the Flatirons awaken you each morning from your bed. Those same views tease your senses from the expansive patios with fully retractable doors that blur the lines from inside to outside. Bathed in natural light from soaring windows and skylights, every detail has been thoughtfully curated. Custom walnut doors and paneling welcome you into the home and invite you to explore. The chef's kitchen is a showstopper-featuring custom cabinetry, an oversized marble island, and top-of-the-line Thermador appliances. The open-concept layout flows seamlessly into a lush backyard oasis, perfect for gatherings or quiet moments of retreat by the fire pit. The primary suite is a haven unto itself with vaulted ceilings, a spa-inspired bath, spacious walk-in closet, and private deck access. With multiple flexible living spaces-including a dedicated home office and media room, this home is ready to adapt to your every need. Located minutes from North Boulder's best hiking trails, cycling routes, farmers markets, and local eateries-yet nestled in the peaceful privacy of a mature, sought-after neighborhood. Elevated living starts here. LIVE BOULDER, LOVE BOULDER!
Unit Size
6,988 Ft²
Days on Market
-
Land Size
0.81 acres
Price per sqft
$1,431
Property Type
House
Property Taxes
$2,470
HOA Dues
-
Year Built
1987

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Last updated: 3 months ago (IRES MLS #IRE1051043)

Price History

Date / Event Date Event Price
Aug 4, 2026 Withdrawn -
Withdrawn
Feb 6, 2026 Listed $10,000,000
Listed
Apr 18, 2025 Listed $11,500,000
Listed
Exquisite secluded sanctuary in the heart of Carolyn Heights. Tucked into one of Boulder's most prestigious enclaves, this estate offers a rare fusion of luxury, privacy, and relaxed sophistication . Set on a serene, tree-lined .81-acre level lot, this 7-bedroom, 5-bathroom oasis is where inspired design meets effortless living. Stunning views of the Flatirons awaken you each morning from your bed. Those same views tease your senses from the expansive patios with fully retractable doors that blur the lines from inside to outside. Bathed in natural light from soaring windows and skylights, every detail has been thoughtfully curated. Custom walnut doors and paneling welcome you into the home and invite you to explore. The chef's kitchen is a showstopper-featuring custom cabinetry, an oversized marble island, and top-of-the-line Thermador appliances. The open-concept layout flows seamlessly into a lush backyard oasis, perfect for gatherings or quiet moments of retreat by the fire pit. The primary suite is a haven unto itself with vaulted ceilings, a spa-inspired bath, spacious walk-in closet, and private deck access. With multiple flexible living spaces-including a dedicated home office and media room, this home is ready to adapt to your every need. Located moments from North Boulder's best hiking trails, cycling routes, farmers markets, and local eateries-yet nestled in the peaceful privacy of a mature, sought-after neighborhood. Elevated living starts here. LIVE BOULDER, LOVE BOULDER!
Jan 20, 2022 Sold
Sold
Sep 30, 2021 Listed $4,950,000
Listed
Show More

Property Highlights

Garage
Fireplace
With View

Building Info

Overview

    General

  • Year Built: 1987
  • Effective Year Built: 2012
  • Building Count: 1
  • Total Rooms: 16
  • Bedroom Count: 7
  • Bathroom Count: 4
  • Full Bathrooms: 3
  • Partial Bathrooms: 4
  • Building Condition: 1
  • Building Quality: 1
  • Construction Type: 6
  • Building Style: 2
  • Exterior Walls Type: 16
  • Interior Walls Type: 3
  • Roof Shape Type: 0
  • Roof Cover Type: 14
  • Floor Count: 200
  • Living Units: 1
  • Floor Cover: 0
  • Basement Type: 6
  • Basement Area: 2,190
  • Garage Type: 1
  • Garage Square Area: 768
  • Parking Space Count: 3
  • Patio Type: 0
  • Porch Type: 8
  • Pool Type: 0

    Dimensions

  • Lot Size Square Feet: 35,311
  • Total Building Area: 7,756
  • Gross Building Area: 7,756
  • Building Area: 6,785
  • Building Area Measurement: L

    Heating and Cooling

  • Air Conditioning: 2
  • Heating: 10
  • Heated Square Feet: 6,785
  • Heating Fuel Type: 0

    Utilities

  • Sewer System: 0
  • Water Service: 0

Building

  • Building Type: 0
  • Property Class: R
  • Subdivision: 21ST/LINDEN SUB - BO
  • Land Acres: 0000000811
  • Standard Land Use Code: 1001
  • County Land Use Code: 1112
  • Legal Description 1: LOT 1 21ST/LINDEN SUB

Neighborhood

  • School District Name: Boulder Valley School District RE-2
  • Census Tract: 012103

Geography

  • Assessors Map Reference: B11-M
  • Account Number: R0004105
  • Parcel: R0004105
  • Lot: 1
  • Meridian: SEC 19 TWN 1N RNG 70
  • Municipality: BOULDER
  • Latitude: 40.0418
  • Longitude: -105.272

    Address

  • Full Address: 3633 21st St
  • Address - House Number: 3633
  • Address - Street Name: 21st
  • Address - Suffix Type: St
  • State: CO
  • City Name: Boulder
  • Carrier Code: C067
  • 4-Digit Zip Code: 1607
  • Zip Code: 80304

Valuation

    Tax

  • Tax Year: 2022
  • Tax Amount: $2,293,518
  • Tax Rate Code Area: 00-010

    Appraisal Valuation

  • Standard Deviation: 0.1517
  • Valuation Date: May 17, 2023
  • Confidence Score: 81
  • Final Value: 5,004,863
  • High Value: 5,764,527
  • Low Value: 4,245,199

    Market Valuation

  • Market Total Value: $5,087,700
  • Market Land Value: $1,371,600
  • Market Improvement Value: $3,716,100

    Assessments Valuation

  • Assessed Year: 2023
  • Assessed Total Value: $344,183
  • Assessed Land Value: $92,789
  • Assessed Improvements Value: $251,394

    Sales

  • Current Sale Contract Date: Jan 14, 2022
  • Current Sale Recording Date: Jan 20, 2022
  • Current Sale Price:
  • Current Sale Document Type: 71
  • Current Sale Input Document Number: 3941335
  • Previous Sale Recording Date: Sep 11, 2017
  • Previous Sale Contract Date: Sep 07, 2017
  • Previous Sale Amount: $3,500,000
  • Previous Sale Document Type: 71
Data used for valuation calculations is provided by RealtyHop, and other third party sources

Comparables

Unit
Status
Type
Beds
Baths
ft²
Price/ft²
Asking Price
Listed On
Closing Price
Sold On
HOA + Taxes

About North Boulder


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Nearby Rentals

Unit for rent at 1240 Cedar Ave, CO, 80304

$1,642 /mo

  • 1 Bed
  • 1 Bath
1240 Cedar Ave, CO, 80304 Listing by Rick Rivera
Unit for rent at 2037 Walnut St, CO, 80302

$1,200 /mo

  • 1 Bed
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2037 Walnut St, CO, 80302 Listing by Rick Rivera


Frequently Asked Questions

When was property at 3633 21st Street built and last sold?
The property at 3633 21st Street was built in 1987 and last sold on Jan 14, 2022 for $4,500,000.
How much is this home worth?
The estimated value of the home located at 3633 21st Street is $9,674,034.
What are some comparable homes to 3633 21st Street?
There are currently no comparable homes to 3633 21st Street.