A brief history of Nacha and the ACH
According to Nacha, the ACH network started in response to the growing number of paper checks being issued and, subsequently, processed through banks, leading to the 1968 formation of the Special Committee on Paperless Entries (SCOPE). At the same time, the American Bankers Association was looking for ways to improve the payment system in the United States.
These two independent developments eventually collided, forming the first regional ACH in California in 1972. By 1974, there were enough regional ACH networks that a larger entity was required to administer the whole thing, leading to the creation of Nacha.