The Priority Pass mobile App and website are useful for navigating the hours, times and locations of all of the Priority Passlounges.

There are Priority Pass lounges at the following US airports.

Atlanta: The Club at ATL - Concourse F, Airside, Upper Level. 06:00-21:30 Daily (Accessible from any gate via Plane Train)

Baltimore: Chesapeake Club Lounge, International Terminal E. Hours Vary, Check PP App.

Chicago: Terminal 5 Only - Air France VIP Lounge. 09:00-20:00 Daily.

Dallas: Accessible from Any Terminal via SkyLink
The Club at DFW - Terminal D. Hours: 07:30-19:30 Daily
AMEX Centurion Lounge Also Available at Concourse D.

Terminal D: KLM Crown Lounge. Hours: 06:00 - 22:00 daily. Near gate D8.
Terminal D: Air France Lounge. Hours: 12:00 - 20:00 daily. Near gate D12.

Las Vegas:
Terminal 1: The Club at LAS. Hours: 06:00-02:00 Daily.
Terminal 3: The Club at LAS. Hours: 08:00-00:00 Daily. Across from Gate E2
AMEX Centurion Lounge Also Available at Concourse D.

Los Angeles:
Terminal 2: Air Canada Maple Leaf Lounge. Hours: 05:00-10:00 & 13:00-23:00 daily
Terminal 2: Air France Business Class Lounge. Hours: 10:00-19:00 Monday, 10:00-20:30 Tuesday & Wednesday. 10:00-23:00 Thursday-Saturday. 10:00-22:00 Sunday.
Terminal 3: The Virgin America Loft. Hours: 06:00-23:30 Daily.
Terminal 6: Alaska Airlines Board Room. Hours: 05:00-22:00 Daily.
Tom Bradley International Terminal (TBIT): KAL Lounge (Airside) - Hours: 08:00-00:00, Monday, Wednesday & Friday. 08:00-16:00, 19:00-00:00 Tuesday, Thursday, Saturday & Sunday. (Closed for cleaning besides those hours). Have a pour your own bar, finger sandwiches and other light snacks.

Miami (3):
Concourse D: Centurion Lounge (see below)
Concourse F: Club America
Concourse J: Avianca VIP Lounge
Concourse J: VIP Lounge Miami

New York JFK (2):
Terminal 1: KAL Business Lounge. Hours: 14:30-20:30 Daily.
Terminal 1: Air France - KLM Lounge. Opening Hours: 06:00 - 02:00 Daily.
Terminal 4: Wingtips Lounge. 24 Hr Access Daily.
See below for Terminal 5 Airspace Lounge

New York LGA:
Central Terminal - Air Canada Maple Leaf Lounge:Landside, Before Security, Concourse A, Level 3. Hours: 05:15-20:30 Daily.
See below for AMEX Centurion Lounge

Orlando (MCO)
The Club at MCO - Near gate 91. 06:00-21:0 Daily (Accessible from gates 70-129)
Phoenix: Terminal 4, The Club at PHX. Hours: 08:00 - 15:30 daily (30 Mar - 24 Oct). 08:00 - 17:30 daily (25 Oct - 29 Mar).

San Francisco (International Terminal, flights departing from Concourse A only)

Seattle (4):
Concourse A: The Club
Concourse B: Centurion Studio
Concourse D: Alaska Airlines Board Room - Near D1
South Satellite: The Club
North Satellite: Alaska Airlines Board Room - Between N1 & N2

Washington IAD:
Concourse A: Air France - KLM Lounge. HOURS: 10:30 - 22:00 daily, but may shutdown after AF departure. Opposite Gate A22.
Concourse B: British Airways Galleries Lounge. STRICT HOURS: 07:00-14:00 Daily. Take train to Concourse B and go up to Concourse Level. (Outside of these hours, OneWorld Sapphire and Emerald members may have access depending on OneWorld Airline and Itinerary.)

AMEX Platinum Cardholders Can Also Access: (See This Thread for More info)
The AMEX Centurion Lounge:
Dallas Ft. Worth (DFW)
Las Vegas (LAS)
Miami (MIA)
New York LaGuardia (LGA) - Main Terminal
San Francisco (SFO) - Terminal 3
Seattle (SEA)

Airspace Lounges:
New York (JFK) - Terminal 5.
Cleveland (CLE) - Post security, Main Terminal just before the B Concourses
Baltimore (BWI) - Concourse D, post-security, near gate D10. Also accessible to other concourses by presenting a same-day BWI boarding pass to Concourse D security.
San Diego (SAN)