He said the Battle of Antietam event - staged Friday, Saturday and Sunday on the 612-acre Artz farm, just south of Hagerstown - also set a record with the largest number of re-enactors, estimated at just over 14,000.
"They were still walking in as early as this morning for the Cornfield battle," Frye said. "We've gone way beyond our expectations. It's been a smashing success."
Organizers had expected Saturday to be the event's peak day, with up to 30,000 spectators attending.
That proved to be an underestimation, said Maryland tourism official Anne Mannix, who estimated more than 40,000 spectators attended the event on Saturday.
Mannix said the estimate was based on the fact that most of the site's roughly 20,000 parking spaces were filled.
She said the day's 15,398 on-site ticket sales couldn't be used as a gauge because it didn't factor in the more than 15,000 weekend passes sold before the event or VIP passes.
Almost all the spectator parking spaces were used Sunday, leading organizers to believe even more people attended than on Saturday, Mannix said.
Friday's crowd was estimated at about 7,000 spectators, including 3,000 school children, she said.
Frye estimated 10,000 spectators were at the Cornfield battle, which began at dawn Sunday.
The Sunken Hill battle re-enactment in the afternoon drew an even larger crowd.
It was a brisk weekend for the event's 96 sutlers, who sell period clothing, accessories, gear and other items, said sutler coordinator George Lomas, who credited the record crowd of re-enactors.
"Most of the sutlers sell to the re-enactors. The spectators help out but mainly we're here to outfit and resupply re-enactors," Lomas said.
Civilian re-enactor Lynn Kalil said she was impressed at how smoothly the event went considering the large numbers.
"I've been doing this 25 1/2 years, and this is the best-organized event I've ever seen," said Kalil, of Royal Oak, Mich., who played a key role in the day's main non-military event.
Her group's mock temperance rally Sunday morning filled the civilian demonstration tent with about 200 people.
Kalil portrayed the head of the Daughters of Temperance in the humorous skit, which featured dramatic speeches on the evils of alcohol and pleas for soldiers to pledge abstinence countered by heckling from drunken Union soldiers.
The nearly hour-long presentation showed spectators a not-so-glorious side of Civil War history - the problem the Union army had with alcoholism, said re-enactor Karen Rae Mehaffey, of Dearborn, Mich.
"It's typical of groups that did visit the camps," said Mehaffey, who co-organized and took part in the rally. "Alcoholism was a great problem due to boredom, fear of battle and homesickness."
Kalil said she thinks it's very important that the non-military side of Civil War history and the critical roles women played in the war effort be represented at re-enactments.
"It's something that's been ignored for years," she said.
The event wasn't without it problems, including a fatal heart attack suffered by a Union re-enactor during the Cornfield battle on Sunday.
A civilian re-enactor from Rochester, N.Y., was seriously burned later that morning, in a chemical explosion at her husband's sutler tent.
Luckily, most of the more than 300 first-aid patients suffered relatively minor problems, including dehydration.
Laura Ernde contributed to this story.