Add Listing
    For Lease
    • For Sale
    • For Lease
    • Recently Sold
    • Property Lookup
    • Brokers
    AI Search
    Back to Search
    The Largest CRE Database in the US with Over 1 Million Listings

    55 Sunnyside Ave Mill Valley, CA

    View on Map
    Claim this Listing
    Loading data...
    Loading data...
    Loading data...
    For Lease
    Contact for pricing

    Former Mill Valley post office available for lease.

    Type:OFFICE
    Property size:
    7,082 SF
    Lot size:
    0.40 Acres
    Added:
    May 20, 2025
    Days on Market:
    341
    Last Refresh:
    Apr 5 at 10:56 pm

    Property Features for 55 Sunnyside Ave

    General Information

    Standard status
    Active
    Size
    7,082 SF
    Lot size
    0.40 Acres
    Property subtype
    OFFICE

    Spaces For Lease

    at 55 Sunnyside Ave Contact us

    We can help!

    Listing Contact
    Brian Foster

    Listing agent Brian Foster

    Listing office Cushman & Wakefield | Larkspur

    Listing date May 20, 2025

    Source Moodyscre

    Displayed information is deemed reliable but is not guaranteed and should be independently verified.

    All listing content including descriptions, pricing, images are the copyrighted material of Cushman & Wakefield | Larkspur

    Overview

    Iconic Mill Valley Building For Lease

    Available for the first time in over 30 years, 55 Sunnyside Ave presents a leasing opportunity in one of Mill Valley's iconic buildings. Formerly the Mill Valley post office, this property is situated in the heart of downtown. The location offers the potential to establish a brand presence. The property features vaulted ceilings and natural light. On-site parking is available. The property has a size of 7,082 square feet. The downtown location provides visibility.
    Property Profile Insight Report Location Intelligence

    Current Use by Public Records

    Office buildings

    Suggested Use

    Law Firm Real Estate Agency Restaurant Spa & Massage Center Dental Office Hair Salon Nail Salon Building Supply Daycare Center Gym & Fitness Center

    Zoning and permitted uses should be independently verified with local authorities.

    Location Insight

    • Map
    • Local Demand
    City
    Mill Valley
    County
    Marin
    State
    California
    Longitude
    -122.545
    Latitude
    37.9063

    Nearby Similar for Lease

    • $53 SF/Yr

      High-Identity Mill Valley Office Space

      Office space with views, convenient location, and modern amenities.
      61 Camino Alto, Mill Valley, CA 94941
      View Details
    • $0.29 SF/Yr

      Mill Valley Office Space Available

      Second-floor office space suitable for medical or general office use.
      147 Lomita Drive, Mill Valley, CA 94941
      View Details
    • $2 SF/Yr

      Office Space with Freeway Access

      Exceptional office space in Mill Valley with convenient freeway access.
      591 Redwood Hwy, Mill Valley, CA 94941
      View Details
    • $3 SF/Yr

      Mill Valley Office Space Available

      Second-floor office space with abundant natural light and open layout.
      655 Redwood Hwy, Mill Valley, CA
      View Details
    • Contact for pricing

      Turn-Key Restaurant in Mill Valley

      Fully equipped restaurant space with outdoor patio in downtown Mill Valley.
      38 Miller Ave, Mill Valley, CA 94941
      View Details
    • Contact for pricing

      Redwood and Glass Office Building

      Office space for lease near San Francisco International Airport.
      495 Miller Ave, Mill Valley, CA 94941
      View Details
    • Contact for pricing

      Mill Valley Shopping Destination

      Iconic shopping center in Mill Valley with diverse dining options.
      800 Redwood Hwy , Mill Valley, CA
      View Details
    • Contact for pricing

      Mill Valley Shopping Center Space

      Retail space available in vibrant Mill Valley shopping center.
      800 Redwood Hwy Frontage Rd, Mill Valley, CA
      View Details
    • $6 SF/Yr

      Renovated Office Space with Views

      Mill Valley office space featuring modern amenities and freeway visibility.
      1 Belvedere Pl, Mill Valley, CA
      View Details
    • $60 SF/Yr

      Prime Office Building For Lease

      Stand-alone building with prominent signage and recent improvements.
      36 Tiburon Blvd, Mill Valley, CA
      View Details
    • Contact for pricing

      Office Space For Rent

      Office space available for lease in Mill Valley, California.
      20 Sunnyside Ave, #E, Mill Valley, CA 94941
      View Details
    • $47 SF/Yr

      Renovated Creative Office Space Available

      Creative office space for lease, fully renovated with parking.
      1060 Redwood Hwy Frontage Rd, Mill Valley, CA
      View Details

    FAQs

    What type of property is this?
    Office building - Former Mill Valley post office available for lease.
    Where is this office building located?
    The property is located at 55 Sunnyside Ave Mill Valley, CA.
    What is the lease rate?
    The lease rate is $54 SF/Yr.
    What are key features of this property?
    This property features: Unparalleled downtown location and visibility in the heart of Mill Valley.; Rare opportunity to lease an iconic building, available for the first time in 30+ years.; The former Mill Valley post office, a recognizable and historic landmark.
    (415) 485-0500 Call to check price and availability
    We can help!
    Contact for Pricing
    Please call us for current price
    and status of this listing
    Brian Foster
    Learn More
    Request Owner's contact information
    Message sent successfully
    Error
    If you are the owner or broker of this property and would like to edit or remove this listing please send a message to web site administrator.
    Message sent successfully
    Error
    Email to Your Friends
    Link copied to clipboard
    Separate multiple addresses with a comma
    Message sent successfully
    Error

    Realmo Value Estimations

    Realmo estimates a property’s market value using a proprietary methodology that incorporates public data and user-submitted information. This cumulative value is generated by integrating a variety of conventional and innovative methods. 

    Disclaimer

    These figures are not official appraisals and should not be used as a substitute for a valuation performed by a licensed appraiser.
    Actual market value may differ due to factors not captured in the data. Estimates are offered for informational purposes only, and users should conduct independent research before making financial or investment decisions.
    By using this feature, you acknowledge that Realmo is not responsible for actions taken based on these estimates.

    AI approach

    Realmo AI Method estimates property value using machine learning models trained on millions of comparable listings, transactions, and market signals. It analyzes property features, location intelligence data, and current market dynamics to predict the most probable market value in real time.

    Realmo CapRate Calculation

    Realmo calculates the Capitalization Rate (Cap Rate) to help estimate a property's potential return on investment. The Cap Rate is a fundamental metric in commercial real estate that measures the relationship between a property's net operating income and its market value.

    How We Calculate Cap Rate

    Cap Rate Formula:
    Cap Rate (%) = (Net Operating Income / Property Value) × 100

    Net Operating Income (NOI) Formula:
    NOI = Area × Lease Rate × (1 - Vacancy Rate) × (1 - Operating Expense Ratio)

    Components

    Net Operating Income (NOI) represents the annual income a property generates after operating expenses:

    • Area: Building square footage from property records
    • Lease Rate: Annual $/sqft based on market data for the property type and geographic location
    • Vacancy Rate: Percentage of unoccupied space based on market data for the property type and location
    • Operating Expense Ratio: Operating costs as a percentage of income, varies by property type

    Property Value is derived from:

    • Recent sale price (if available)
    • Statistical models using comparable sales
    • AI-powered valuation estimates

    Example Calculation

    For a 100,000 sqft Office Building:

    • Lease Rate: $25.00/sqft/year (market data for Office in this area)
    • Vacancy Rate: 8% (market data for Office in this area)
    • Operating Expense Ratio: 35% (typical for Office properties)
    • Property Value: $15,000,000

    Step 1: Calculate NOI

    NOI = 100,000 × $25.00 × (1 - 0.08) × (1 - 0.35)
    NOI = 100,000 × $25.00 × 0.92 × 0.65
    NOI = $1,495,000/year

    Step 2: Calculate Cap Rate

    Cap Rate = ($1,495,000 / $15,000,000) × 100
    Cap Rate = 9.97%

    Property Type Considerations

    Net Operating Income calculations vary by property type due to different operating expense ratios:

    • Office: Higher expenses (30-40%) for HVAC, utilities, maintenance
    • Retail: Moderate expenses (25-35%) for common area maintenance
    • Industrial/Warehouse: Lower expenses (15-25%) for minimal tenant services
    • Multifamily: Moderate expenses (35-45%) including property management
    • Self-Storage: Lower expenses (25-35%) due to minimal maintenance

    Market lease rates and vacancy rates are specific to each property type and geographic location, reflecting local market conditions.

    Disclaimer

    These calculations are estimates for informational purposes only and should not be used as a substitute for professional financial analysis or appraisal.

    • Cap Rate calculations depend on market data that may change over time
    • Actual operating expenses, lease rates, and vacancy rates may differ from market averages
    • Individual property conditions, lease terms, and tenant quality significantly impact actual NOI
    • Property value estimates are approximations and not official appraisals
    • Cap rates vary widely by market, property condition, and investment risk profile

    Professional Guidance Recommended: Before making any investment or financial decisions, consult with licensed appraisers, commercial real estate brokers, and financial advisors who can evaluate your specific property and circumstances.
    By using this feature, you acknowledge that Realmo is not responsible for investment decisions or actions taken based on these estimates.

    Cap approach

    Capitalization Method calculates value based on estimated net operating income (NOI) and applying a market-based capitalization rate (cap rate), we estimate what a typical investor might be willing to pay for it.

    Comparable approach

    Comparable estimate is based on recent sales of similar nearby properties, adjusted for factors like size, condition, and location.

    Relative

    Relative property class coefficient uses factors that account for typical price differences between various asset types (e.g., retail vs. industrial) to provide a more accurate market-aligned estimate.

    Geo

    Comparable Sales Method, enhanced by Geo coefficients — location-based adjustment factors that reflect differences in price levels across neighborhoods, cities, or regions ensuring a more accurate, market-sensitive valuation.

    Stat Estimate

    This method estimates value based on actual market adjusted recent (~5 years) sales of comparable properties around by location and property type.

    • Ranges - area data calculated by industry standard IQR Outlier Removal Method
    • Range-from: 75% of all similar sales ($/sqft) are above this value
    • Range-to: 75% of all similar sales ($/sqft) are below this value
    AI Estimate

    This method estimates value based on AI market estimation of comparable properties around by location and property type.

    • Ranges - area data calculated by industry standard IQR Outlier Removal Method
    • Range-from: 75% of all estimations ($/sqft) are above this value
    • Range-to: 75% of all estimations ($/sqft) are below this value
    Alternative use

    Estimate considers the property’s potential value if used for a different purpose-based on zoning, demand, and market feasibility.

    More about this property
    Thanks! Your message was sent.
    Error! Your message wasn't sent.
    Please enter your name
    Please enter email
    Please enter the email in the correct format
    Please enter phone
    Please enter the number in the correct format
    Please enter message
    Thank You

    You are Unsubscribed From Notifications

    Google sign-in failed. Please try again or use another login method.
    Sign Up Successful!
    You now have access to more from Realmo!