1807 to 1835 (Embargo of 1807, Great Fire of 1811, War of 1812 (which continued to 1816), and financial and political setbacks from 1816 to 1825)(Though not mentioned in contemporary records, a tunnel system (limited to extensive?) seems to have been created to smuggle goods from off the docks
Newburyport was fabulously wealthy from 1740 to 1807 and most of the huge Federal mansions built in the city come from that time. Huge reserves of wealth were present just before the setbacks starting in 1807. This would be the resource and the justification for building tunnels under the City of Newburyport. Many of the merchants went from extreme wealth to utter poverty when the Great Fire occurred. Some fled the city for Boston and other parts; but a good number stayed. Mysteriously, some of them actually prospered.
As Newburyport is very proud of being the Birthplace of the U.S. Coast Guard; the main reason it became that was the rampant acts of smuggling that were occurring out of Newburyport. Therefore, it was imperative as the fifth most important port in the new United States; to have a revenue cutter up and active first thing in 1791 to put a stop to it or at least slow it down.
Most smuggling occurred as ‘slight of hand’. A ship’s cargo coming into port for the 19th century and earlier was largely unknown. A ship would be partially unloaded off-port or would slip quietly into an obscure wharf for partial unloading. The ship’s manifest altered accordingly and then the vessel would proceed to the customs house for reporting. Most customs agents were short-staffed, and there were corrupt “pilots” who would be complicit in guiding the ship into an obscure wharf. As much as a third of the cargo would then be smuggled duty free and transported to waiting eager markets.
Most smuggling amongst merchants was done on a gentleman’s unwritten agreement. Never mentioned with no paper trail and no testimony.
According to court records at the Sham-Robbery Trial, the defendant (from Maine) picked Newburyport as his place of committing a crime (Dec, 1814) and then blaming it on the city’s residents; because it was well known that Newburyport was a major center for smuggling during this time period.