Welcome Home! This inviting and well cared for 3 bedroom with 1 oversized bathroom home is ready for its next owner. The kitchen was updated in 2021and 2022 upgrades includes new windows, siding, and a metal roof. Complete with a detached garage and brand-new driveway completed in 2025. Add everyday convenience, and there's plenty of storage throughout the house to keep life organized. A comfortable, move in-ready home with the important updates already done.
3 bedrooms, 1 bathroom, about 700 sq ft, works out to roughly $601 per square foot. Chat with Zara if you'd like a deeper read on whether this detached fits your budget and timing.
Inside 21 Mariam St
Every detail from the listing, in one place.
Type
Detached
Style
Bungalow
Living space
700-1100 sq ftas stated on the listing
Parking
4 spacesYes garage
Basement
Partially Finished
Features & systems
Parking & garage
Garage
Yes
Parking spaces
4
Interior
Basement
Partially Finished
Lot & land
Lot size (sqft)
0
Listing & possession
Property style
Bungalow
Property class
Detached
21 Mariam St Price & Sale History
Earlier listings of this property, list-price changes, and the most recent annual property tax on the listing.
Independent mortgage broker · OAC · rates subject to change and underwritingMortgage Squad →
Referral disclosure: Summitly may refer you to Mortgage Squad Advisors, an affiliated mortgage partner. You are free to choose any lender or mortgage professional.
Monthly cost
Enter a rate to see the monthly cost
An estimate, not a quote. Utilities and insurance are extra.
Affordability calculator
Estimated monthly payment
$2,068
/mo
based on the purchase price of $420,999
$84,200 cash
$336,799 financed
$283,673 total interest
Principal54%$336,799
Interest46%$283,673
20% down · 25-yr amortization · 5.50% rate. Principal & interest only — taxes, condo fees, and insurance not included.
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Figures are Summitly estimates for illustration only — not from TRREB or the MLS® feed, and not a mortgage approval, appraisal, or financial advice.
Rental income potential
Est. monthly rent
low–high
Gross yield
rent × 12 ÷ price
Cap rate (est.)
net of tax + fees
Summitly AI estimate for discussion only — not from TRREB or the MLS® feed, and not an appraisal or investment advice. Yield and cap rate are derived from the estimated rent versus the asking price.
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Mortgage financing is arranged through Mortgage Squad Advisors. Summitly is the technology platform that powers this site. Estimated values, AI insights, calculator results, and rental projections shown on this page are generated by Summitly and are not provided by, reviewed by, or sourced from TRREB, the MLS®, or the listing brokerage; they are not appraisals or opinions of value. The trademarks REALTOR®, REALTORS®, and the REALTOR® logo are controlled by the Canadian Real Estate Association (CREA) and identify real estate professionals who are members of CREA. The Coldwell Banker® name and logo are trademarks of Coldwell Banker Real Estate LLC.
Similar homes for sale nearby in St. Thomas
Other 2–5 bed homes for sale in St. Thomas around $421K.
Average days on market43Homes sold in about 43 days on average.
Sale-to-list ratio97.6%On average, homes sold below asking.
Active listings237Homes for sale here right now.
Median vs prior 90 days+0.2%Compared with May 14 – Aug 12, 2026: prices up.
Based on 232 sales from Aug 12 – Nov 10, 2026 (171 in the prior 90 days). Aggregate MLS® figures for closed sales; individual sold prices are shown only to signed-in members.
Questions About 21 Mariam St
How much is 21 Mariam St listed for?
21 Mariam St is listed at $420,999 (MLS® X13452562). Summitly updates the price as soon as the MLS® record changes.
Is $420,999 a good price for 21 Mariam St?
Summitly rates it Well Above Market: the asking price is 15% or more above Zara's estimate, an estimate built from recent sales in St. Thomas. The rating is an automated opinion, not an appraisal; "What's it worth?" on this page shows how it is worked out. See Zara's estimate
Has the price of 21 Mariam St changed?
Yes — it was first listed at $432,000 and is now $420,999, a drop of $11,001 (2.5%).
How many bedrooms and bathrooms does 21 Mariam St have?
21 Mariam St has 3 bedrooms and 1 bathroom, with about 700–1,100 square feet of living space. It is a detached home in St. Thomas.
How much would the monthly mortgage be on 21 Mariam St?
About $2,068 a month — principal and interest on $420,999 with 20% down ($84,200), a 25-year amortization and an assumed 5.5% interest rate. The mortgage calculator on this page lets you change the down payment, amortization and rate.
How does 21 Mariam St compare with other homes in St. Thomas?
Its asking price of $420,999 is about 19% below the median sold price in St. Thomas over the last 90 days, $521,000, across 232 closed sales on the TRREB MLS®. A city median mixes every type and size of home, so the comparable sales on this page are the closer guide.
Has 21 Mariam St been sold before?
Summitly has no earlier MLS® sale or lease of 21 Mariam St on record from the last two years. Older records aren't shown under TRREB rules.
Where is 21 Mariam St?
21 Mariam St is in St. Thomas, ON. Schools, transit, parks and shops nearby are under Location & lifestyle on this page.
How long has 21 Mariam St been on the market?
147 days — 21 Mariam St was listed on June 16, 2026.
What is the price per square foot of 21 Mariam St?
About $383 to $601 per square foot: the asking price of $420,999 over the 700–1,100 sq ft the listing gives as its size range.
Does 21 Mariam St have parking or a garage?
Yes — the listing gives 4 parking spaces. Garage: Yes.
Does 21 Mariam St have a basement, and is it finished?
The listing describes the basement as: Partially Finished.
