Southern RR Findley Ave Roundhouse in Birmingham, AL. Vacant, gutted.
IT was the home of the steam excursion locos back in the day.

Martinsburg, W.Va., full circle house (former B&O, apparently a standard design for that road) with interior turntable, plus two shop buildings and the ruins of a second roundhouse destroyed by fire in the 1980s, all originally constructed in 1866-1872 to replace an earlier facility destroyed in the Civil War; notable as the site of Stonewall Jackson's "locomotive raid" in 1861, and also considered the possible point of origin of the first national labor uprising in 1877.

All this is across the tracks from the Martinsburg station that serves Amtrak (Capitol Limited) and Maryland commuter trains, and which was originally built as a hotel in the pre-Civil War era; converted to a station following the same Stonewall Jackson activity that destroyed the original roundhouse and station in 1861.

Also from the B&O is the roundhouse (former car repair shop) that is the centerpiece of the B&O Museum; built later than the one in Martinsburg (1880s?) to a different design, also a full circle job, with interior turntable. This one was mentioned in an earlier comment in this thread.

Am not sure, but supposedly the Union Railroad near Pittsburgh still had a roundhouse with a turntable. This was the facility that dictated a new transfer engine design be built with a unique 0-10-2 wheel arrangement as the biggest thing that would fit on the turntable. Is that one still around?

Another one that might still be around is a modern (late 1940s) NKP roundhouse in Belleview. Can anyone comment on it?

Off the top of my head in New England:
(not mentioned above)

Plainville, MA - Ex NH, no tracks/no table, now used as a garage.
Chester, MA - Ex B&A, derelict.

Portsmouth, NH - Ex B&M, derelict.
North Conway, NH - Ex B&M, home of Conway Scenic Railroad.
Bartlett, NH - Ex Maine Central, under restoration. (no table)
West Lebanon (Westboro) NH - Ex B&M, derelict. (no table)
North Walpole, NH - Ex B&M, home of Green Mountain Railroad.

Woodstock, VT - Ex Woodstock RR Enginehouse, no tracks/table, now used as a garage. Reported for sale.

Willimantic, CT - (reconstructed NH) Home of Connecticut Eastern Railroad Museum

Simpson timber Co. has a roundhouse and turntable at Shelton, WA

All Norfolk & Western

1) Norfolk Va. Locomotive Service (Active Rail Service with Table)

[url] https://www.google.com/maps/@36.8736243 ... a=!3m1!1e3[url]

2) Roanoke VA. Car Shop (Presently Maint. Shop) (Active Rail Service with Table)

[URL] https://www.google.com/maps/place/Roano ... cbdbb0989b [url]

3) Bristol VA. (Privately Owned) (No Rail Service or Table)

[url] https://www.google.com/maps/place/Brist ... 7948d7dbf1 [url]

4) Williamson WV. (Car & Maint. Shop) (Active Rail Service with Table)

[URL] https://www.google.com/maps/place/Willi ... dd00be3cd9 [url]

Just to name a few…

The Union Railroad Roundhouse still exists, although Im not sure if it is still in use or not.
Two other roundhouses exist in the Pittsburgh Area with the removal of the one at Conway Yard. A Monongahela Connecting roundhouse now used by CMU, and a McKeesport Connecting Railroad Roundhouse, which is derelict but standing.

I also believe the B&LE still has a roundhouse in Greenville PA. Not sure if this is used or not either.

And Pitcarin PA has its PRR Roundhouse Backshop still surviving as a MOW base, the only part of the few roundhouses at that yard to survive.

Here a a couple of facilities that have not yet been mentioned:

East Ely, Nevada
The rectangular engine house of the former Nevada Northern.

Kahului, Maui Island, Hawaii
Concrete roundhouse formerly used by the Kahului Railroad. Also a connected machine shop.

I'm in Atlanta, GA. We have one turntable still in use at CSX Tilford Yard. Its part of the engine servicing facility and its very easy to see from the roads near by. I remember the round house that was around until 10 or 15 years ago. An inspection pit remains along with 3 tracks on the old building foot print one with a new building over it.

Next we have the old John St Roundhouse from the Southern RR. The building is part of Bauder Fashion College.

Next is the remnant of the Roundhouse at Pegram Shops Southern RR (featured in the "Walking Dead")

Though not a Roundhouse, there is the old Pullman Shops in east Atlanta. It was home to the New GA in the 1980's. It has a transfer table that was operable in the New GA days. Most recently featured in "Catching Fire" -second in the "The Hunger Games" trilogy.

Add to the list for Vermont:

Burlington: Ex-Rutland RR, now VRS, still in use.
White River Jct.: Ex-CV. Technically doesn't count; the original house burned in 09 or so and this replaced it. It is not used by a RR.

And add to New York:

Troy: Ex Boston and Maine. This fairly large, early roundhouse is in use by a heating and oil company.

That's all I can think of.

92. D&H roundhouse, Rouses Point/Champlain, NY

93. Winona, MN: Green Bay and Western enginehouse, two tracks, now part of a barge-loading operation.

94. Hayfield, MN: Chicago Great Western enginehouse, two tracks, now part of a plastics company.

Ryan Heath
Rochester, MN

Edit: changed numbers to reflect the fact that 93 directly follows 92...

The original RYPN thread was "Roundhouse Database" and started in 1998

viewtopic.php?f=1&t=210&start=15

The NRHS was maintaining a database but apparently not any more, or at least its not on their website.

95. Roswell, Colorado Springs, CO. CRI&P.
https://www.google.com/maps/@38.866831, ... a=!3m1!1e3

Not mentioned so far:
Clarkdale, Arizona, Verde Canyon/Arizona Central, ex-AT&SF; turntable removed but at least three stalls still used as "car shop" for the Verde Canyon.