Looking to stretch your legs this September? You have plenty of interesting options: You can run a marathon while half-submerged in a pool (if you can afford it), or complete a half-marathon alongside Amish runners through bucolic Lancaster County.

Friday, Sept. 7

• Teri's Run & Twilight Walk, 5k, 7 p.m., Downingtown, $25

Saturday, Sept. 8

• Bird-in-Hand Half Marathon, 13.1-mile run through Amish farm country, 7:30 a.m., Lancaster County, $75 online registration
• Nationwide 4.01k Walk/Run at the Philly Zoo, 4.01k, 8:30 a.m., Philadelphia Zoo, $30
• Noell Maerz Patriot Games Triathlon, run-canoe-bike-run, 7:30 a.m., New Britain (Bucks County), $200 per team
• Big Red Run and Harmony Walk, 5k, 8 a.m., Upper Merion, $25
• Philadelphia Undy 5000, 5k run/walk in your boxers, start time 9 a.m., Martin Luther King Drive, Philadelphia, $30 ($40 race day) 

Sunday, Sept. 9

• 9/11 Heroes Run, 5k, 2p.m., West Chester, $25
• Hit the Hay 13K, 8.06-mile run, 9 a.m., Birdsboro, $35 ($27 w/o shirt)
• HydroWorx Underwater Marathon, 5k, 10k, half and full marathon all on underwater treadmill run, 7 a.m. and 1 p.m., Troeg's Brewery/Hershey Park, Hershey, $750-$6,500 (fundraising run)

Saturday, Sept. 15

• Caron's 5k Run and Sober Q, 5k, 9 a.m., Ridley Creek State Park, $25
• Yards 5k Beer Run, 10:30 a.m., Yards Brewing Company, Philadelphia, $30

Sunday, Sept. 16

• Barracuda 70.7 Triathlon, 70.7-mile run-swim-run-swim-run-bike-run, 8 a.m., Hazleton (Luzerne County), $155/individual, $195/team
• Marshman Triathlon, 1/4 Mile Swim, 12.5 Mile Bike, 2 Mile Run, Marsh Creek State Park, $123, 7:30 a.m.

Tuesday, Sept. 18

• Run For Your Life, 5k, start time 6 p.m., 16 Great Valley Parkway, Malvern $15 ($20 race day), benefits East Whiteland Volunteer Fire Association and Community Volunteers in Medicine

Sunday, Sept. 23

• ScoutStrong Fitness Fest (PDF flyer), 5k and 1 mile walk/run, 10:30 a.m., East Goshen Park, $20 (adult 5k race-day)
• Woodlawn Trustees Trail Series 5k, trail run, 9 a.m., Chadds Ford, $20

Saturday, Sept. 29

• 5k 2kare 4kids, 5k run, start time 10 a.m., Ridley Creek State Park, $25/individual 
• Hands On House Half Marathon, 5k run, 13.1-mile circuit run, start time 9 a.m. Children's Museum of Lancaster, $60 (half-marathon race day), $30 (5k race day)

Sunday, Sept. 30

• Zane's Run, 5k run and walk, 7:30 a.m., Sugartown Elementary School, Malvern, $25, benefits Families of Spinal Muscular Atrophy. Features chip-timing new this year.

Hat tips to RunningintheUSA.com and RunTheDay.com for race information.