How to Build a Little League Pitcher’s Mound

Introduction

Every play begins on the bump, so how to build a pitchers mound isn’t just trivia—it’s the foundation of fair, safe baseball. Follow this guide to meet current Little League® regulations while creating a durable surface pitchers love.

Tools & Materials Checklist

• Transit level or string line
• 50 ft tape measure
• Shovel, rake, grading board
• Mound clay bricks & bulk mix
• 2 × 6 in boards for plateau frame
• Hand tamp or plate compactor
• Garden hose & sprinkler
• 18 in pitching rubber
• Mound tarp (10 ft Ø)

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Little League Pitcher’s Mound Dimensions

Pitching rubber distance

• 46 feet (front edge of rubber to back point of home plate)

Pitchers mound diameter

• 10 feet

Pitchers mound height

• 6 inches (ages 10 and under) 8 inches (ages 11 to 13)

Pitchers rubber size

• 18 inches long x 4 inches wide

Pitchers mound slope

• 1 inch drop per 1 ft, starting 6 inches in front of the rubber

Step-by-Step Pitchers Mound Construction

Constructing a regulation-grade Little League pitcher’s mound that survives a full season of rainouts, double-headers, and bullpen sessions demands precision, not brute force. A single mis-measured inch in height or slope can alter pitch trajectory and invite injuries. While many leagues bring in turf specialists for the heavy lifting, coaches and volunteers armed with the right tools—and the step-by-step roadmap below—can absolutely nail the job in a single afternoon.

1. Locate & Mark the Circle

• Drive a nail 46 ft from home plate.
• Swing a 5 ft string radius to trace a 10 ft circle.

2. Excavate & Rough Grade

• Remove turf to a uniform 1 inch depth.
• Rake the sub-base level.

3. Frame the Plateau (5 ft × 3 ft)

• Center the 5 × 3 ft frame so its front edge sits 6 inches in front of the rubber position.
• Check level in all directions.

4. Pack Clay in 1-Inch Layers

• Blend a 40-40-20 clay/sand/silt mound clay mix.
• Add water until the soil holds shape.
• Spread 1 inch, tamp firm, repeat to target height.

5. Shape the 1 in-per-ft Slope

• From the plateau’s front edge, grade the drop: 1 in vertical per 1 ft horizontal.
• Verify with a 2 × 4 and level.

6. Install & Level the Pitching Rubber

• Set the 18 inch rubber flush with plateau top, square to home plate.
• Re-tamp edges to prevent shifting.

7. Moisturize & Finish

• Lightly sprinkle water, rake smooth, tamp footprints.
• Cover with a portable pitching mound tarp to cure overnight.

Maintenance & Repair Tips

• Brush and spot-tamp daily to hold slope.
• Keep moisture consistent; dry clay cracks quickly.
• Patch landing area weekly with fresh mound clay bricks.
• Always cover your pitcher’s mound after play protect it from the elements.

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FAQs

What clay mix should I use for a Little League mound?

• A 40 % clay / 40 % sand / 20 % silt blend delivers firmness plus drainage.

How often should I re-tamp the mound?

• Light tamping after every practice or game keeps the surface safe and consistent.

What is the correct pitchers mound slope?

• Start 6 inches in front of the rubber and drop 1 inch per foot toward home plate.

Can I build a portable pitching mound for backyard practice?

• Yes—prefab portable pitching mounds in 4-, 6- and 8-in heights let you train anywhere and protect game turf.