The Tomhannock Creek chondrite has been analysed, with the following results: Fe 11·36, Ni 1·69, Co 0·07, FeS 5·26, SiO₂ 36·88, TiO₂ 0·135, Al₂O₃ 1·80, Cr₂O₂ 0·30, FeO 14·94, MnO 0·31, MgO 23·81, CaO 1·39, Na₂O 0·73, K₂O 0·095, P₂O₅ 0·36, H₂O+ 0·34, C 0·10; total 99·57. The mineralogical composition is olivine (Fo₈₁), hypersthene (En₈₃), plagioclase (An₂₂), nickel-iron, troilite, chromite, and probably apatite. The density of the meteorite is 3·65.

Tomhannock Creek is not identical with Homestead, nor with Yorktown. Yorktown is a chondrite that appears to have fallen near Yorktown, Westchester County, New York (41° 17′ N., 73° 49′ W.), in September 1869.