Never bothered to count. Haven't skied outside the U.S. yet.
For 2019-20 I added Bryce in VA and Cataloochee in NC because of the Indy Pass. Added Deer Valley using Ikon. Spent a couple hours at Howelsen Hill in Steamboat Springs the day that me and my friends drove to Denver for flights home.
EDIT 3/4/21: added Canaan Valley, Monarch, Wolf Creek, Copper, Loveland
EDIT 2/25/23: added Catamount, West Mountain, Windham from Feb 2022; Winter Park in Dec 2022
EDIT 6/1/24: added Vail, Beaver Creek, Keystone, Breck, Crested Butte from 2023-24
SOUTHEAST (mostly since 2004)
Sugar, NC
Beech, NC
Cataloochee, NC (Indy)
Wintergreen, VA
Massanutten, VA (home mountain since 2004-05)
Bryce, VA (Indy)
Snowshoe, WV
Winterplace, WV
Timberline, WV
*Canaan Valley, WV (Indy)
MID-ATLANTIC
Blue Knob, PA (DCSki gathering 2013, 2016)
Elk, PA
Whitetail, PA
Roundtop, PA
Montage, PA
Plattekill, NY
Belleayre, NY
*Hunter, NY
*Windham, NY
NORTHEAST (mostly 2013-19)
North Country School campus ski hill, NY, rope tow (1968-70)
Whiteface, NY (1968-70 with NCS, 2014-2016)
Gore, NY
*West Mountain, NY (Indy)
*St. Sauveur, QUE
*Tremblant, QUE
Stowe, VT (3 days in 1970 with NCS, 2014, 2017)
*Smuggler's Notch, VT
Mount Sunapee, NH
Loon, NH
Wildcat, NH
Tenney, NH
*Attitash, NH
*Bretton Woods, NH
Waterville Valley, NH
*Cannon, NH
Wachusett, MA
Jiminy Peak, MA
*Berkshire East, MA
*Catamount, MA/NY (Indy)
Sunday River, ME
Killington, VT
*Pico, VT
*Sugarbush, VT
*Mad River Glen, VT
*Stratton, VT
WEST - mostly after 2008
Alta, UT (1970, 1982, regularly starting 2008)
Snowbird, UT
Brighton, UT
Solitude, UT
Deer Valley, UT
Snowbasin, UT
Powder Mountain, UT
Bridger, MT
Big Sky, MT
Grand Targhee, ID/WY
Jackson Hole, WY
Sun Valley, ID
Steamboat, CO
*Howelsen Hill, CO
Arapahoe Basin, CO
Snowmass, CO
Aspen Mtn aka Ajax, CO
Aspen Highlands, CO
Buttermilk, CO
Telluride, CO
Winter Park, CO
*Monarch, CO
Wolf Creek, CO
Copper, CO
*Loveland, CO
Vail, CO
*Beaver Creek, CO
*Keystone, CO
*Breckenridge, CO
Crested Butte, CO
Taos, NM
* Santa Fe, NM
Heavenly, CA/NV (Mar 2000)
*Kirkwood, CA (Mar 2000)
Homewood, CA
Alpine Meadows, CA
*Sugar Bowl, CA
Squaw Valley, CA
Northstar, CA
Mammoth, CA
Mt. Rose, NV
*Mt Hood Meadows, OR
Mt. Bachelor, OR
* - 1 day only