Robert Heysham Sayre (October 13, 1824 – January 4, 1907) was vice president and chief engineer of the Lehigh Valley Railroad.

Sayre was born on October 13, 1824, to William Heysham Sayre and his wife, Elizabeth Kent, on the Kent family's farm near Bloomsburg in rural Columbia County, Pennsylvania.

[3] Sayre's first significant work in engineering was on the Morris Canal in New Jersey.

He also participated in the surveys and construction for the Mauch Chunk Switchback Railway.

Sayre built a large house in Bethlehem, where he lived from 1858 until his death in 1907.