Well this is what I got after some research. A lot of the information is due to you guys- -I just compiled it.
And feel free to add any that I may have missed.
Remains of Roundhouses and their turntables (2013).
* Phillips: narrow gauge 8 stall roundhouse and armstrong turntable located on Wesley Spear Rd. The rh is built on the foundation of an "old stone fort".
* Alna: 3-stall shed (jct. of Cross St. and Rt. 218). Narrow gauge museum that has started construction on a new roundhouse and turntable close by.
* Bangor: footprint of house, no table, little remains. rh torn down in 2010.
* Waterville: roundhouse and turntable are in use by Pan Am and Guilford railroads.
* Rockland: roundhouse and turntable still in use. Restored to Maine Central colors.
* Rumford: roundhouse and turntable still in use. large yard that is not very accessible to the public.
* Millinocket: rh and tt in bad condition, 3 stalls, near station Rd.
* Hermon (N. Maine Jct.): rh on Diesel shop Rd. no table.
* Calais: remains of filled table pit, rh in good condition, off of Poorhouse Ave.
* Derby: table and house in yarding, OK condition.
* Caribou: table and house in OK condition off of riverfront St.
* S. Portland: Rigby yard, only roundhouse footprint and table base are left. Not accessible to the public. was in use until 2010.
* Portland: roundhouse used by several businesses and is in good condition. no table.
* South Berwick: partially preserved table, house foundation, on the corner of Fifes lane.
* Standish: the table is near the boat launch. no roundhouse-used to have one.
* Stockton Springs: only the inspection pits of the rh exist. They are located inside the "Y" of the train tracks.
* Houlton: house has been demolished leaving only a small shack and turntable.
* Oakfield: the end of Yard Rd. (dirt road) are some remnants of a roundhouse footprint. no table.
* Portsmouth: very bad condition (by fire and rot), both house and table are there. Brick.
* Bartlett: restored wooden house, no table. Restoration by Bartlett preservation club.
* N. Walpole: house and table are in good condition.
* W. Lebanon: roof rotted, bad condition, both house and table are there.
* Keene: 17-stall roundhouse on Gilbo Ave. Now a shopping plaza. no table.
* N. Conway: restored rh and tt. In use by Conway scenic railroad.
* Dover: house in good condition. Now owned by Salmon falls stoneware (a pottery business). no table.
* Nashua: partial business, only one stall remains, between Temple St. and Amory St. no table.
* Stratford: turntable, maybe no house, near route 3.
* Wakefield: in the community of Sanbornville. Bits of roundhouse foundation, restored turntable.
* Claremont (Claremont jct.): 3-stall shed, still in use.
* Rochester: floor\foundation of a house is in a KFC parking lot. no table.
* Wolfeboro: in the community of Fernald. Two-stall shed that stores small trains.
* Hyannis: house and table. The table is filled in to be a volley ball court. good condition.
* Revere: five stall, brick, off railroad St. no table.
* E. Deer Field: house and table may still be in use, large yarding.
* Chester: house roof rotted, table looks filled in.
* Haverhill: filled table at the end of Mulberry and Hale St. no house.
* Athol: a brick roundhouse is in good condition, very little remains of the turntable.
* Fitchburg: filled in table, no house. A line from the yarding goes over the table.
* Plainville: 4-stall house on west Bacon St. The table ring can clearly be seen on the ground.
* Whitman: preserved turntable.