- 3 Wynnefield Heights, Pennsylvania
- 19 Wynnefield, Pennsylvania
- 18 Wynnewood, Pennsylvania
- 17 Wyoming
- 17 Wyoming Avenue
- 1 Wyoming Valley
- 2 Wythburn, England
- 5 Xenia, Ohio
- 3 Xerxes I, King of Persia, 519-465 or 4 B.C.
- 2 Xylophones
- 1 Yale & Towne Mfg. Co. (Firm)
- 1 Yale College (1718-1887). Linonian Society
- 2 Yale Lock Manufacturing Company
- 1 Yale University
- 5 Yard ornaments
- 1 Yardmen
- 36 Yards
- 5 Yarmouth, Nova Scotia
- 13 Yarn
- 6 Yarnall & Cooper, Architects
- 1 Yarnell & Goforth, Architects
- 12 Yates, David G.
- 2 Yawning
- 3 Yeast
- 1 Yeaton & Harris Manufacturing Co.
- 8 Yellow fever
- 1 Yellow Fever Epidemic of 1793
- 3 Yellowstone Lake
- 39 Yellowstone National Park
- 1 Yerkes & Plumb Edge Tool Factory
- 1 Yewdall's Woolen Factory
- 4 Yewdell's Factory
- 1 Yiddish (language)
- 1 Yocom's City Iron & Brass Foundry
- 5 Yokohama, Japan
- 1 Yonkers, New York
- 1 York and London Assurance Office
- 1 York County, Pennsylvania
- 1 York Haven, Pennsylvania
- 1 York Minster, England
