3421 4th Street, Boulder, CO 80304

• 6 beds |
• 5 baths |
• 5,022 sqft

Property Description

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.

Listing Status:

Active

Data Last Updated:

April 2, 2026 at 4:22PM

Listing Office:

Colorado Realty 4 Less, LLC : 9705317448

Listing Agent:

Kathleen Haas : 970-531-7448

MLS ID:

IR1053821

Interior

• General: Eat-in KitchenFive Piece BathOpen FloorplanVaulted Ceiling(s)Walk-In Closet(s)
• Appliances: DishwasherDisposalDown DraftMicrowaveOvenRefrigeratorSelf Cleaning Oven
• Basement: DaylightFull
• A/C: Evaporative CoolerCeilin
• Heating: Forced AirHot WaterRadiant
• Fireplace: Family RoomGasGas LogLiving Room

Exterior

• General: Bath
• Style: Contemporary
• Other Structures: DeckPatio
• Parking: OversizedParking spaces: 2

Construction

• Roofing: Composition
• General: Three Or More

Location

• Road/Access: Public
• Originating MLS: recolorado
• School District: Boulder Valley RE 2
• County: Boulder

Lot

• Zoning: SFRLOT 2 & NWLY TRI LOT 1 3403 FOURTH STREETR0108936
• View: Mountain(s)
• Fencing: FencedPartial

Utilities

• Utilities: Cable AvailableElectricity AvailableInternet Access (Wired)Natural Gas Available
• Water: Public
• Sewer: Public Sewer

Financial

• Source: recolorado
• Exclusions: Furnishings and Personal PropertyWater Rights Included