According to the Iranian Students' Tourism & Travelling Agency (istta)

The figure shows over 14 percent more than that of a month earlier, marking a monthly record for arrivals as the influx of visitors bolsters the economy.
Some 85 thousand foreign travelers visited Isfahan in the first calendar month Farvardin, setting a new record for the past 40 years, Zargarpour announced earlier in April, adding that figure showed 800 percent surge in comparison to the same period last year.
Isfahan is Iran’s top tourist destination for good reason. Its profusion of tree-lined boulevards, Persian gardens and important Islamic buildings gives it a visual appeal unmatched by any other Iranian city, and the many artisans working here underpin its reputation as a living museum of traditional culture.

Source: Tehran Times