Questions: Completed in 1825, this 360-mile-long engineering marvel connected industrious manufacturing centers of the Atlantic seaboard with thriving midwestern farms of the Ohio River Valley, which would open a new world of consumers and come to symbolize the successes associated with early American infrastructure improvements during the first half of the 19th century? The Baltimore and Ohio Railroad The National Road The American Telegraph System The Erie Canal

The answer is The Erie Canal.

The Baltimore and Ohio Railroad was one of the oldest railroads in the United States, but it was not completed until 1830. It was significant in connecting the eastern seaboard with the Midwest, but it does not match the description of a 360-mile-long project completed in 1825.

The National Road, also known as the Cumberland Road, was the first major improved highway in the United States built by the federal government. Construction began in 1811, and it was an important route for westward expansion, but it was not completed in 1825 nor was it 360 miles long.

The American Telegraph System refers to the network of telegraph lines that began to be developed in the mid-19th century, particularly after Samuel Morse's successful demonstration in 1844. It does not fit the description of a 360-mile-long engineering project completed in 1825.

The Erie Canal was completed in 1825 and stretched approximately 363 miles from Albany to Buffalo, New York. It connected the Atlantic Ocean with the Great Lakes, facilitating trade between the eastern seaboard and the Midwest. It was a significant engineering achievement of its time and played a crucial role in the economic development of the United States during the 19th century.