(Photo: Getty Images)

The basics:
The city's celebration is older than the country itself, dating back to 1762. Strictly marchers only (no cars or floats allowed), this year's 249th annual parade begins with a blessing from Cardinal Timothy Dolan, archbishop of New York, who will celebrate Mass at St. Patrick's Cathedral at 8:30 a.m.—not long before crowds start gathering along the parade route.
• Wednesday, March 17, 11 a.m. to approximately 5:00 p.m.
• The parade begins at 44th Street and Fifth Avenue and proceeds north along Fifth Avenue to 86th Street.
• Free

The best vantage points:
• Any spot along Fifth Avenue toward the north end of the parade route, far from the midtown crowds and NBC camera crews.
• The steps of the Metropolitan Museum of Art (1000 Fifth Ave., at 82nd St.) are a good bet, since marchers often pause outside the nearby American Irish Historical Society.
• The official viewing stand lies at 64th Street, and free tickets are available for bleachers running from 62nd to 65th Streets. Seating is on a first-come, first-served basis. Call 718-231-4400.

The participants:
• Cardinal Dolan officially reviews the parade and greets crowds from the steps of St. Patrick's Cathedral.
• Mayor Bloomberg marches along with a crop of local politicians.
• New York City Police Commissioner Raymond Kelly, who's serving as this year’s grand marshal.
• Niall Burgess, counsel general of the Consulate General of Ireland.
• Royal Canadian Mounted Police, as well as members of the NYPD.
• Fire Department commissioner Salvatore Cassano marches with other FDNY members.
• Bagpipe bands hailing from Ireland, of course, and around the world.
• High-school bands from across the country.

The television coverage:
• Armchair spectators can tune in to NBC (Channel 4), which will be taping live from 11 a.m. to 3 p.m. at various points along the parade route.