Ronald Reagan's inaugural parade will begin with 50 horsemen on black stallions carrying state flags and end with 300 members of the Mormon Tabernacle Choir leading the president and others in singing "The Battle Hymn of the Republic."

In between will come 31 bands, 29 equestrian units, two floats, hundreds of military marches, hot air balloons, and a dog sled from Alaska, Parade Chairman Terry Chambers said yesterday.

The District's Cardozo High School marching band and the regimental band from the Virginia Military Institute in Lexington are the only two area bands in the parade.

Area equestrian units include Kena Shrine Temple Palominos from Fairfax, American Indian Heritage Foundation from Falls Church, and the First Maine Cavalry of Accokeek, Md., officials said.

Reagan wanted his inaugural parade, which is being called "America -- A New Beginning," to be "a sea of young faces . . . young Americans marching down Pennsylvania Avenue," said Chambers. He may have succeeded -- the average age of the military marchers is 19, he added.

Reagan will watch the parade, which will begin at 2:15 p.m. at the West Front of the Capitol, from a reviewing stand across the street from the White House. Tickets for 12,000 bleacher seats close to his reviewing stand are being sold by the inaugural committee for $100 each. About 6,000 seats, across from the White House but away from the president, are priced at $75 each.

Along 15th Street, the committee is setting 4,000 tickets at $25 each. The cheapest 2,500 parade seats, priced at $15 and located across from the District Building, already have been sold to out-of-town Republicans, officials said.

Tickets to the parade are being sold at the Union Station Visitors' Center where inaugural officials have erected dozens of highly decorated booths to disperse an estimated 200,000 tickets to the 40,000 guests invited to various inaugural events.

Gen. Omar Bradley, the country's only surviving five-star general, is the honorary grand marshall of the parade. Bradley, 87, also will be honored Jan. 19 at Reagan's entertainment gala.

Chambers said the parade is being planned to tell the history of America from the Revolutionary War until the 1900s, with marchers and horsemen dressed in costumes. A 100-foot-long, 30-foot-wide, red, white, and blue float representing Southern states and a float shaped like a cornicopia representing mid-America are scheduled for the parade. The mid-America float will carry the Purdue University Male Glee Club. The Morman choir, representing western America, will ride on a moving stage, Chambers said.

After the parade, former Washington TV weatherman Willard Scott will host a free musical concert on the West Front of the Capitol, which will feature such groups as the Emerald Society Bagpipe Band of the New York City Police Department. Officials have planned a massive fireworks display after the music, calling it the largest fireworks show ever held in Washington.

Officials also said they would keep the parade short, at Reagan's request, so that the television networks would broadcast it. Chambers believes his parade, with its fast-paced 110 step-per-minute cadence, will take about 1 hour and 15 minutes.

"President-elect Reagan has asked for a short, snappy parade," said Chambers, who has helped plan 20 Tournament of Roses parades. "The bands that are invited are among the very best in the country in their class."

Until this year, it was customery for a band from each state to march in the parade. Officials said bands excluded from the parade may be invited later this year to perform outside the White House for tourists.