There are at least seven Different Tour Companies that tour guests on the Freedom Trail: 

The Freedom Trail Foundation :Daily tours every hour on the hour from 11-4 from Boston Common, every hour on the half hour from 10:30-3:30 from Faneuil Hall (Bostix Booth from April-November. Limited tour availability in off-season. Check thefreedomtrail.org for details. These are the official tours of the Freedom Trail Foundation. 

Boston National Historical Park: FREE Tours of the Freedom Trail led by National Park Service Rangers. Daily tours begin in mid April and continue through November. All tours begin at the Faneuil Hall Visitor Center. Going on your own? Download the FREE mobile app at go.nps.gov/bostonapp.

Freedom Trail Run: Group runs: Sat/Sun @ 8:30am, Daily runs: by appointment, open year round.

Lessons on Liberty: Daily tours: Mon-Fri 10am, 1:30pm, 2:30pm, Sat/Sun 10am, 12:30pm, 1:30pm, 2:30pm

BostonCityWalks.com  Year-Round Tours Daily at 10 AM and Tuesday Evenings at 6 PM - History and Historic Architecture

The Histrionic Academy: Seasonal tours at 10:30am & 11:30am

Boston Town Crier: Seasonal tours Mon-Friday 9:30am, 12:30pm, and 3:30pm, Sat/Sun at 9:30am & 3:30pm.

Here is a link to several free freedom trail maps, including one in Google Maps.  http://www.stevestravelguide.com/free...

There is an excellent tour guide now on Amazon.  Also, ditto the thoughts on the National Park Service tours.  They are excellent and free.

 

  Great Family Tour 

Freedom Trail Run - runners enjoying post-run ferry ride!

Freedom Trail Run Post-Run Ferry Ride

 

Boston Adventures Freedom Trail Scavenger Hunt- Super-fun and educational

A fantastic way to see Boston in just a couple hours! For those interested in history, landmarks and cultural attractions, contact Boston Adventures for more details, the fun is all here! See Quincy Market , Faneuil Hall, Boston Common , The North End , Paul Revere's House , USS Constitution and a lot more. Offering Boston Common or Faneuil Hall starting locations. Park in Faneuil Hall or under the Boston Common or take public transportation to meet Boston Adventures.