Block and Section (Texas)

In the Texas Survey System, a Block & Section reference identifies a one-square-mile parcel within a named railroad survey grant. It is the dominant TXSS convention in West Texas — the Permian Basin, Trans-Pecos, and Panhandle — and it looks superficially like a PLSS section reference but is anchored differently.

A typical Block & Section reference reads:

Block 5, Sec 14, T&P Survey, Reeves County

This means: Section 14 of Block 5 within the Texas and Pacific Railway Company Survey (T&P), located in Reeves County.

What "Block" and "Section" Mean Here

• A block is a large rectangular area of a 19th-century railroad land grant. Blocks are numbered within each railroad's survey — Block 1, Block 2, and so on. The block is roughly the Texas equivalent of a PLSS township, but its size and shape vary by railroad.
• A section within a block is one square mile (~640 acres), similar to a PLSS section. Sections are numbered within each block.
• The railroad survey name (T&P, H&TC, GC&SF, etc.) identifies which railroad's land grant the block belongs to.

Critically, block numbers are scoped to each railroad survey. There is no statewide Block 5 — there are many Block 5s, one in each railroad survey that has one. The unambiguous reference combines all four pieces: county, survey name, block, section.

Why Block & Section Exists

After Texas joined the Union in 1845, the state owned millions of acres of public land in the Trans-Pecos and Panhandle. Between the 1850s and 1880s, Texas issued land grants to railroads as inducements to build track. The railroad companies surveyed their grants into blocks and sections so they could sell off parcels to settlers.

This is why Block & Section descriptions feel more grid-like than other TXSS shapes — they were designed for systematic resale by the railroads.

Common Railroad Surveys

These are the railroad survey names you will most often see in Block & Section references:

For the full reference, see Blocks and Sections.

Disambiguation

If a description omits the survey name and the block number exists in multiple surveys within the same county, the reference is ambiguous. Township America's resolver returns candidate matches in that case so the caller can pick the right one.

Reading a Block & Section Reference

Equivalent forms you may see:

• Block 5, Sec 14, T&P Survey, Reeves County
• Blk 5 Sec 14 T&P, Reeves Co.
• Section 14, Block 5, T&P RR Co. Survey, Reeves

Township America's parser normalizes abbreviations like T&P, T & P, and Texas and Pacific Railway Company Survey to a single canonical name in the response.