Memory Alpha
Memory Alpha

The decks of Constitution-class Federation starship:

Original configuration

Constitution-class schematic

Constitution-class deck configuration

A schematic of Constitution-class hull pressure compartments

In the script of "Court Martial", sections 18Y to 27D of B deck were said to be "near" engineering, though the final version of the episode changes this to refer to someone in sections 18Y to 23D of B deck as "near or in" engineering. The same area of the ship was also referred to as containing the vessel's weapons room, though this statement isn't included in the final edit of the installment.
In ultimately unused dialogue from the final draft script of "Charlie X", deck five was said to be the location of Charles Evans' quarters during his time aboard the USS Enterprise, and all the lab circuitry aboard the ship ran through the main corridor on that deck.

Refit configuration

Constitution-class refit deck configuration

In a scene included in the script for Star Trek VI but not in the final version of that film, Deck 18 (referred to as "R Deck") was said to include science laboratories.

Background information

The following deck layouts come exclusively from the Star Trek Encyclopedia, by Michael Okuda and Denise Okuda.

Major features
(original configuration)
Major features
(refit configuration)
1 Bridge 1 Bridge
2 Science labs 2 Science labs
3 Science labs, life support 3 Science labs, environmental support
4 Crew quarters 4 Crew quarters
5 Crew quarters, including Captain's quarters 5 Crew quarters, including Captain's quarters
6 Crew quarters 6 Crew quarters
7 Sickbay, transporter room, briefing room, computer core, impulse engines 7 Sickbay, transporter room, computer core
8 Food preparation, recreation deck, ship's laundry, life support 8 Food preparation, recreation deck, ship's laundry
9 Freight and cargo 9 Freight and cargo
10 Freight and cargo 10 Freight and cargo
11 Phaser controls 11 Phaser controls
12 Interial dampening system, observation deck 12 Interial dampening system, observation deck
13 Observation deck, dorsal interconnects 13 Photon torpedo launcher
14 Engineering support, water storage 14 Engineering support, water storage
15 Deuterium fuel storage 15 Warp drive reaction upper core injectors
16 Deuterium fuel storage 16 Deuterium fuel storage
17 Crew quarters 17 Deuterium fuel storage
18 Power distribution subsystems 18 Main power transformers, sensor subsystems, deflector subsystems
19 Main Engineering, Hangar deck 19 Main Engineering, shuttlebay, navigational deflector, long range sensors
20 Shuttlecraft maintenance 20 Shuttlecraft maintenance, cargo bays 13-18
21 Life support systems, cargo bays 21 Environmental systems, cargo bays 19-20
22 Cargo bays 22 Botanical section, security confinement
23 Antimatter storage pod 23 Tractor beam emitter, antimatter storage pod

The following deck layouts come from The Making of Star Trek, by Stephen Whitfield for the original configuration primary hull and from Mr. Scott's Guide to the Enterprise, by Shane Johnson for the refit configuration.

Major features
(original configuration primary hull)
Major features
(refit configuration)
1 Bridge, secondary phaser control 1 Bridge, V.I.P. docking port, emergency batteries
2 Primary research labs, technicians' work areas and duty stations 2 Security chief's office, Temporary holding cells
3 Primary research labs, technicians' work areas and duty stations 3 Kitchen, dining area, V.I.P. (Officers') lounge
4 Crew quarters (junior officers', passenger) 4 V.I.P. quarters, junior officers' quarters, conference room
5 Crew quarters (junior officers', passenger), senior officers' quarters 5 Senior officers' quarters, including Captain's quarters
6 Crew quarters (junior officers', passenger), main engineering 6 Crew quarters, crew mess rooms, crew's lounge, personnel airlocks, gangway hatch, turbolift maintenance, impulse engineering, impulse deflection crystal, fusion reactors
7 Sickbay, water and bulk storage, main computer core 7 Auxiliary control, sickbay, transporter rooms, briefing room, armory, rec deck, bowling alley and racquet ball facilities, chapel, cargo storage, life support, water tanks, battery systems, waste recovery, saucer section landing struts, main brig, gymnasium.
8 Recreation area (outdoor simulation), holographic entertainment center, main mechanical food preparation, laundry, main computer core (lower part) 8 Main docking ports, explosive bolts for separation, planetfall ramp, auxiliary fire control, laundry, fabrication facility
9 Cargo and freight storage, technicians' repair shops 9 Viewing lounges, specialized passanger cabin
10 Cargo and freight storage, technicians' repair shops 10 Primary hull circuit breaker room, specialized passanger cabin
11 Primary phaser control facility 11 Main sensor array monitoring station, specialized passanger cabin
12 12 Photon torpedo storage, torpedo exhaust system
13 13 Photon torpedo room, torpedo tubes, docking ports, auxiliary torpedo fire control
14 14 Engineering computer monitoring room and bay
15 15 Main engineering, horizontal intermix chamber, dilithium reactor room, landing bay control room
16 16 Power converters (M/ARAs), secondary hull main battery room, Chief engineer's office, briefing room, primary maintenance, turbolift repair, landing bay observation galleries, landing bay tractor beam
17 17 Emergency transporters, circuit breaker room, cargo storage inspection balcony, docking ports, landing bay.
18 18 Cargo storage, secondary hull auxiliary control, shuttlecraft hangar, lifeboats
19 19 Cargo storage, cargo transporters, shuttlecraft maintenance
20 20 Matter/antimatter storage, botanical garden and lab, regulation pool sun deck, tractor beam housing
21 21 Matter/antimatter storage (lower part), tractor beam, waste recovery, water tanks, swimming pool

A detailed partial cutaway sketch of the refit configuration

There is a discrepancy in The Making of Star Trek with the description of the primary hull as being eleven decks in height, but shown to be nine decks in height in a cutaway diagram. The secondary hull is stated to be sixteen decks in height, but shown in the diagram to be eight decks, with no exact locations given for the following features: fuel storage, supplies storage, main repair centers, water and waste reconversion, minimal quarters for engineers and star-drive personnel used only in the case of saucer separation and the hangar deck.

Constitution-class schematics created by Doug Drexler for ENT: "In a Mirror, Darkly, Part II"

The most recent canonical cutaway graphic of the original Constitution-class was featured in ENT: "In a Mirror, Darkly, Part II". The graphic was originally produced by Doug Drexler for the Star Trek: Captain's Chair CD-ROM. [1](X) It was also featured in the The official STAR TREK prop and costume auction catalog, pp. 36-37. [2] In this image several key locations of the interior of the ship are recognizable as depictions, some are marked and labeled. The schematic depicts the ship as having 27 decks, and one more above deck 1 in the nacelles. The marked areas in this layout are:

Major features
(original configuration)
1 Main bridge
2 Stellar cartography (upper part), forward phasers t/b, field impeller (in the nacelles, behind the bussard ramscoops) and the warp coils (eight coils in each nacelle)
3 Stellar cartography (lower part)
5 Crew quarters
6 Turbo shaft (horizontal), impulse deck (upper part)
7 Sickbay, transporter rooms, briefing room, the impulse deck (lower part)
8 Arboretums
9 Cargo bays (saucer section, upper part)
10 Cargo bays (saucer section, lower part)
11 Forward phasers
12 Planetary / perimeter sensor dome t/b (saucer section)
18 Auxiliary control, small craft ops (above hangar door), power transfer conduits (four conduits run through each pylon)
19 Shuttle bay (upper part), Main engineering (upper part)
20 Shuttle bay (mid part), Main engineering (mid part)
21 Deflector / long range sensor, main engineering (lower part), Shuttle bay (hangar deck)
22 Aft phasers (below hangar door)
23 Warp core (horizontal)
25 Cargo bays (upper part)
26 Cargo bays (lower part)