Spending by visitors from across the Atlantic leapt by 28% to Â£633m in the 12 months to the end of September.
Visitor numbers from the region also rose during the third quarter of last year to their highest level since 2011.
However, there was a 7% drop in visitors from European markets.
The statistics came from UK tourism data published by the Office for National Statistics (ONS), with further analysis from the Scottish government and tourism body VisitScotland.
Overall, the number of overseas visits to Scotland rose by 0.3% over the year to September, while spend increased by 6.3%, according to the ONS International Passenger Survey.
VisitScotland attributed the sharp rise in North American visitors and spend to a weaker pound and an increase in airline capacity between Scotland and the region.
It also cited safety and security concerns for the fall in visits from core European markets such as France and Germany.
On a more positive note, there was a rise of nearly 50% in visitor numbers from Eastern European markets.
VisitScotland chief executive Malcolm Roughead said: "It is remarkable to see such unparalleled growth in the North American market in both visits and spend.
"Of course, a favourable exchange rate has played its part, but a focus on airline capacity and connectivity - with around 90,000 extra seats on services from North America in 2016 - alongside a concentrated marketing approach has proved a real formula for success.
"It is disappointing to see a slight dip in European visits from core markets such as France and Germany, but with uncertainty over safety and security during 2016 in these countries, it is perhaps understandable."
Tourism Secretary Fiona Hyslop said: "North America is an important international market. These excellent figures confirm visitors from the region continue to spend more when they visit Scotland.
"It's great news for our hotels, shops and restaurants that depend on tourism revenue."
The Scottish Tourism Alliance said the latest visitor figures were "very encouraging" but warned that tourism businesses in Scotland were facing "numerous challenges".
Chief executive Marc Crothall said: "The rising costs of doing business is a major concern for tourism businesses at the moment, most pertinently the significant increase in business rates, which for some hospitality and licensed trade businesses will be up to 200%.
"This on top of rising costs of goods and services, insurance, licensing, the Apprenticeship Levy and National Living Wage rises will put many smaller businesses in jeopardy.
"Our ability to recruit, grow and strengthen our tourism workforce from EU countries and manage the widening skills gap that exists within the industry remains a key concern for most tourism businesses."
Spending by North American tourists in Scotland has hit a record high following a surge in visitor numbers from the region, according to new figures.