Decks 1-5 are fully located within the primary hull. The primary hull is also known as the saucer section or the upper hull.
Deck 1	Bridge. Captain's Ready room (located on the starboard side on the bridge) Briefing Room ( also known as conference room,  located on the port side of the bridge). Turbolift shaft caps. Externally: upper sensor platform. two escape pods spacesuit lockers aft bridge airlock XOs Office Weapons locker
Deck 2	Messhall (section 13 ) Captain's Private Dining Room (Cabin 125-Alpha.) Officers' quarters V.I.P. quarters. Laboratories and storage. Sensor gear. Escape pod access.
Deck 3	Captain's quarters. Officers' quarters V.I.P. quarters. Photon torpedo trackers and equipment.
Deck 4	Aft Photon Torpedo Launchers Lower Cargo bays 1 and 2. (See note below.) Transporter rooms 1 and 2. Phaser maintenance. Sensor gear. Escape pod access.
Deck 5	Sickbay. (section 15 alpha) Medical facilities comprise: a treatment area housing three biobeds a surgical bay with the primary biobed complete with diagnostic instruments Jefferies tube access is located beside one of the biobeds. doctor's office medical laboratory which includes a replicator and storage area; further medical and/or medical storage facilities morgue Sensor gear. Escape pod access.
Decks 6-9 span both the primary hull and the secondary hull. The primary hull is also known as the saucer or as the upper hull. The secondary hull is also known as the engineering hull or as the lower hull.
Deck 6	Holodecks 1 and 2. Armoury Externally: auxiliary deflector Primary hull: Auxiliary computer core, which spans through Decks 6 and 7 Primary hull: Escape pod access. Secondary hull: Deuterium (matter) processing Secondary hull: Consumables resupply connectors
Deck 7	Primary hull: Auxiliary computer core, which spans through Decks 6 and 7. Primary hull: Upper cargo bays 1 and 2. Primary hull: Laboratories. Primary hull: Escape pod access. Primary hull: RCS (reaction control system) thrusters and access. Secondary hull: Deuterium tanks. Secondary hull: Warp engine core injector access.
Deck 8	Primary hull: Deuterium processing. Primary hull: Port and starboard/forward docking ports. Primary hull: ODN (optical data network) and EPS (electroplasma system) main trunks. Primary hull: Lower cargo bays 1 and 2. Secondary hull: Deuterium tanks. Secondary hull: Warp engine core. This spans through decks 8 -13. Secondary hull: Aft workpod storage. Secondary hull: Science/Engineering laboratories. (Section 22) Secondary hull: Astrometrics laboratory.
Deck 9	Primary hull: Cargo loading doors. Primary hull: Aerowing shuttle dock. (AeroWing is the Captain's Yacht located on the underside of the primary hull.) Primary hull: Laboratories. Security Personnel Quarters Secondary hull: Upper main shuttlebay. (Accessed via Deck 10.) Secondary hull: Warp engine core. This spans through Decks 8 to 13.
Decks 10-15 are wholly comprised within the secondary hull. The secondary hull is also known as the engineering hull or as the lower hull.
Deck 10	Main shuttlebay Main computer core. This spans through Decks 10 and 11. Forward torpedo launchers Warp engine core. This spans through Decks 8 to 13. Reserve (auxilary) warp engine core.This spans through Decks 10 to 14. Main Navigational Deflector. This spans through Decks 10, 11 and 12. Primary long-range sensor package located immediately behind the main navigational deflector.
Deck 11	This is known as "wing"-level, i.e. level with the warp nacelle and associated main hull structure (presumably when not raised for warp speed). Main Engineering  Deflector control (Section 59) Life support including artificial gravity controls Chief Engineer's office. Warp engine core. This spans through Decks 8 to 13. Reserve (auxiliary) warp engine core. This spans through Decks 10 to 14. Main computer core. This spans through Decks 10 and 11. Main Navigational Deflector. This spans through Decks 10, 11 and 12.
Deck 12	Antimatter tankage. Warp engine core. This spans through Decks 9 to 13. Reserve (auxiliary) warp engine core. This spans through Decks 10 to 14. Navigational controls. Environmental controls. Main Navigational Deflector. This spans through Decks 10, 11 and 12. Escape pod access.
Deck 13	Warp engine core. This spans through Decks 9 to 13. Reserve (auxiliary) warp engine core. This spans through Decks 10 to 14. Brig. Aft tractor beam emitter Engineering Crew quarters. Engineering Laboratories. Escape pod access. Secondary ODN (optical data network) and EPS (electroplasma system) Trunks
Deck 14	Antimatter processing. Reserve (auxiliary) warp engine core. This spans through Decks 10 to 14. Escape pod access. Ground Hover Footpad Systems
Deck 15	Antimatter loading port. Forward Tractor Beam Emitter Plasma relay room Ground Hover Footpads (Landing Struts)

Source(s): 'Star Trek: Voyager' Companion'  and Star Trek: Voyager Technical Guide V1.0 or: "Yes, but which button do I push to fire the phasers?" by Rick Sternbach and Michael Okuda. Page 10