While the European grain markets became increasingly interconnected from around 1820, the USA did not join this well-integrated international grain trade until after the Civil War (1861–1865). The image shows the wheat exchange in New York in 1906.
Wheat Pit, New York, Produce Exchange, black-and-white photograph, 1906, unknown photographer; image source: NYPL Digital Gallery, Image ID: 801562, https://digitalcollections.nypl.org/items/510d47e0-cd7b-a3d9-e040-e00a18064a99.