At least 30 U.S. companies celebrate their 100th anniversary in 2023 and only two are public, including Walt Disney Company. Of the 27 that are privately-owned, 17 are generational family companies and one is employee-owned. Here is the list I have gathered to date: please let me know if I have missed one.
Albanese Butcher, NYC, 3rd generation
Avalon Theater, Grand Junction CO
Borr's Shoes, Holland MI
Bradbury Stamm Construction, Albuquerque NM, 4th generation
Burns Chevrolet, Gafney SC
D'Arrigo Brothers, Chelsea MA, 3rd generation
Durable Corp., Norwalk OH
Estwing Manufacturing, Rockford IL, family
Geissler's Supermarkets, East Windsor CT, 4th generation
Goedecke Decorating, Bedford NH, 4th generation
Harbor Food Groups, Kent WA, 4th generation
John A. Marshall, Lenexa KS, 4th generation
Lake GM Auto Center, Devils Lake ND
L.H. Hayward & Co., Harahan LA, 4th generation (Camellia Beans)
Li-Lac Chocolates, NYC NY
Lou Mitchell's, Chicago IL, 2nd generation?
Luck Companies, Manakin Sabot VA, 4th generation
McNamara Sports, Merced CA, family
Meinholdt's Welding & Machine Shop, Topeka KS
Old Point Financial, Hampton VA
Paielli's Bakery, Kenosha WI, 3rd & 4th generations
Perfect Building Maintenance (PBM), New York City NY, 3rd generation
Phillips Flowers, Chicago IL, 3rd & 4th generations (?)
R.H. White Construction, Auburn MA, 3rd generation
Sunnyside Ford, Holden MA, 3rd generation
Superior Die Set, Oak Creek WI, 4th generation
Walt Disney Company, Burbank CA, public
Wendell August Forge, Mercer PA
West Pharmaceutical Services, Exton PA, public
W.W. Norton & Co., NYC, employee-owned (publisher)