The same material goes by half a dozen names depending on which state you're in. Crusher run in Virginia is 21A. In the Carolinas it's ABC. In the Midwest it's road base or Type 2. In Texas it might be caliche or crushed limestone base. This guide translates the local names so you know exactly what to ask for at your quarry — wherever you are.
No matter what state you're in, ask the quarry: "Does this material include fines — stone dust and fine particles — or has it been washed clean?" Fines present = road surface material. Washed clean = drainage material only. This one question overrides all naming confusion.
21A is the standard road base/crusher run equivalent. 21B is a slightly coarser gradation. Both contain fines and compact well. Available at most Virginia quarries year-round.
ABC and crusher run are used interchangeably in the Carolinas. Both are well-graded 3/4" minus with fines. Granite is the dominant source rock. High-quality material with excellent compaction characteristics.
Limestone is the dominant quarried stone throughout Tennessee and Kentucky. Crusher run limestone is widely available and reasonably priced. #4 limestone refers to a specific gradation used for road base.
GAB (Graded Aggregate Base) is the engineering specification term used in Georgia DOT specs. For private roads, "crusher run" is the standard term. Granite available in Piedmont region; limestone in the northwest.
Type 2 and 304 are ODOT/INDOT specification numbers that quarries use locally. All are crusher run equivalents. Limestone dominates throughout the Great Lakes region. Excellent freeze-thaw performance.
Stone type varies significantly by region — trap rock in northern NJ/eastern PA; bluestone in upstate NY; granite in New England. All crusher run equivalents work the same way. "Processed gravel" at pits means natural rounded material — confirm it has fines before ordering.
Caliche is the dominant road base material across central and western Texas — a naturally occurring calcite-cemented material that hardens dramatically in wet/dry cycles. Flex Base is the TxDOT specification term for engineered road base. Excellent performance in the Texas climate.
Chat is a unique regional material — fine crushed byproduct of historic zinc mining, available cheaply in northeastern Oklahoma and southeastern Kansas. Functions like decomposed granite as a road surface. Crushed limestone available throughout the region.
Standard crusher run terminology throughout the region. High rainfall makes drainage design especially important. Silty clay subgrades are common — geotextile fabric under base course is strongly recommended throughout the lower Mississippi valley.
Class 5 is the MnDOT specification number that has become the standard market term throughout Minnesota and neighboring states for crusher run equivalent. Widely available at gravel pits throughout the region. Frost heave is a major design consideration — base depth of 8"+ recommended.
Class 6 (CDOT specification) is the standard crusher run equivalent in Colorado. Caliche appears in New Mexico and Arizona. Decomposed granite is widely used in the Southwest for pathways and light-duty driveways. Arid climate means calcium chloride effectiveness is lower — millings or DG are preferred surface options.
Basalt is the dominant road rock in the Pacific Northwest. "5/8 minus" refers to the maximum particle size and is equivalent to crusher run. Very high annual rainfall means drainage design is critical — plan for waterbar or rolling dip every 50–100 feet on any slope over 5%.
| Region | What to Ask For | Common Local Name |
|---|---|---|
| Virginia/Maryland | 21A or DGA with fines | 21A, 21B |
| Carolinas | ABC or crusher run | ABC, Crusher Run |
| Tennessee/Kentucky | Crusher run limestone | Crusher Run, #4 Limestone |
| Southeast | Crusher run with fines | Crusher Run, GAB |
| Midwest/Great Lakes | Type 2 or 304 limestone base | Road Gravel, Type 2, 304 |
| Northeast | Dense graded aggregate or crusher run | DGA, Crusher Run, Processed Gravel |
| Texas | Flex Base or caliche | Flex Base, Caliche, Base Rock |
| South-Central | Road base with fines | Road Base, Chat, Limestone |
| Minnesota/Dakotas | Class 5 or road gravel | Class 5 |
| Southwest/Mountain | Class 6 or road base | Class 6, DG, Road Base |
| Pacific Northwest | Crushed rock, 5/8 minus | 5/8 Minus, Ballast, Crushed Rock |
See also: Gravel types explained in full | Calculate how much you need | Road base buyer's guide