Who invented the telegraph?

The practical electric telegraph system was invented by Samuel Morse in 1837.

After Joseph Henry discovered electric induction in 1831, enabling further development in electrical telegraphy, the first practical telegraph was invented by Dr. David Alter of Elderton, Pennsylvania, in 1836.

It wasn't until 1837 that Samuel F.B. Morse would successfully invent the electric telegraph which would become commercially successful. He did so with the help of financier and assistant Alfred Vail. The Morse-Vail Code would become the international standard mode of communication on the high seas, until Morse Code as well as the S.O.S. distress call were disbanded in 1999.

One reason for the success of Morse's system was that it could be operated over a single wire of lesser quality, and over a long distance. Telegraph wires were strung along railroad lines in many areas.