Drawing Lines on the Map of Marin

By Dewey Livingston

The iconic 1873 Map of Marin County, California (detail) by Hiram Austin depicts rancho boundaries, the county line, townships, school districts, and property lines. (The bold line depicts a potential route for the North Pacific Coast Railroad, which in the end did not take that route.) Anne T. Kent California Room Collection.

For millennia the Coast Miwok people lived on the land we now call Marin County, and did not need maps to guide their way or delineate boundaries. The neighboring families and cultural groups recognized ephemeral borders, marked by language variations in addition to physical markers. To the Miwok people, it was no doubt strange and shocking to have Europeans arrive, take possession of their land and food sources, and apply boundaries forcefully backed by the interlopers’ legal system.

The first property lines drawn in Marin were on paper, based mostly on geographical features, and these proved to be further devastating to the Indigenous peoples. The Mexican government awarded land grants, called ranchos, and placed the new arrivals in charge of the property. The grantees were required to present their intended rancho boundaries to the authorities, and so they drew a pictorial map of the land, called a diseño.

Copy of a diseño of Rancho Corte Madera del Presidio (left of center) and including Rancho Saucelito at left. Note Mission San Rafael at extreme upper right, and Angel Island at bottom. These Mexican-era land divisions were the first to be mapped on what would become Marin County. University of California at Berkeley, Bancroft Library Collection, via Online Archive of California.

In many cases, the chosen boundaries were a creek, ridgeline, or edge of a marsh; these might be connected or closed by a tangent (straight line), and often a rock outcropping or tree marked a corner. In some cases, like Rancho San Geronimo, the rancho boundaries enclosed a watershed. These plots of land were never square — in most cases they echoed the lay of the land, and made for an interesting pattern on a map.

Aaron Van Dorn’s picturesque map of Marin was the first published of the whole county, in 1860. It clearly depicts the land grants in the county. University of California at Berkeley, Bancroft Library Collection.

Things changed when California became a state. Since the founding of the republic surveyors across the United States had been laying out a strictly-observed grid across the land: township and range lines that delineated square sections of land, using, in the case of northern California, the Mt. Diablo Baseline (east-west) and the principal meridian (north-south) as base control. Each section measured 640 acres and was subdivided into quarters and eighths. These provided a framework for the division and sale of public land across the country. When the government surveyors got to Marin, they found almost no public land; the rancho lines had been already drawn, and those were decidedly not very tidy. (Not only Marin, but much of the land in the new state had been divided under the rancho system.)

Mexican citizen rancho owners and their successors had to deal with a new authority and prove their land boundaries, and the federal government was tasked with making sense from these comparatively primitive diseño maps and land divisions, some by then physically marked by fences. The federal government sent out surveyors — in Marin’s case, R. H. Matthewson did most of the surveys — to update and correct the Mexican-era boundaries. This led to a number of disputes both on the ground and in court, and even in some cases the removal of lands from a long-time Mexican owner; attorney fees also forced some Mexican landowners to sell while fighting for their grant.

Detail of the Plat of Rancho Olompali, 1859. The Public Land Commission required new survey maps of the Mexican land grants, resulting in these detailed maps. Here we see natural boundaries — San Antonio Creek on the north and the Petaluma River marshes on the right — with tangents completing the survey. The dotted line on the right is the current route of Highway 101 into Sonoma County. Marin County Recorders Office.

So here we were with an almost-artistic puzzle of land grants as seen on a map, many shapes and sizes — the smallest was Rancho Isla de los Angeles (Angel Island) at 740 acres, the largest the 56,807-acre Rancho Nicasio. But not all of Marin had been successfully granted to an individual, leaving small pockets of unclaimed property, the result of poor initial mapping. These got the township and range treatment: a grid bounded by a strange organic shape floating among the established rancho lands. The unclaimed lands were then put up for sale or homesteading, administered by the federal government. The major example of this was an area on the southeast slopes of Mt. Tamalpais ranging from Mill Valley to Corte Madera, and also some isolated parcels like at Richardson’s Island near Corte Madera. (See this article for more about Richardson’s Island.)

Islands in the Marsh: A High School Instead of Coney Island

The oddly shaped area of unclaimed land sandwiched between the future sites of Mill Valley and Corte Madera was measured into sections, like much of the country outside of Marin. This land was sold to non-grantees. Curiously, a gridded townsite is drawn at Corte Madera (top), which never existed. This is a detail of Van Dorn’s 1860 map. University of California at Berkeley, Bancroft Library Collection.

When the rancho boundaries were settled — most within a decade of statehood — the new local government had already been working on further dividing up the land for administrative purposes. First, in September of 1850, the new county established four townships, which in 1862 was expanded to eight: San Rafael, Novato, San Antonio, Tomales, Nicasio, Point Reyes, Bolinas, and Sausalito.

While most people think of a township as a town (or city) it is not; a township is a way to efficiently divide land into manageable sections for purposes of government organization. A township in terms of public lands was a six-mile-square area, but in places like Marin, which was not sectionalized, the boundary of each township was based on existing rancho lines and natural features. This is often confusing to researchers; it is common to read that so-and-so had a farm in Nicasio in 1865, when actually the farm was 25 miles away on Tomales Bay north of Marshall. That’s because the farm was recorded as being in Nicasio township, which was a very large area.

Austin’s hand-colored 1873 map, detail shown above, shows the large townships of San Rafael and Saucelito, which are to be distinguished from the towns themselves. Anne T. Kent California Room Collection.

In 1855 the county was divided into three supervisor districts, now expanded to five. The obvious need for schools and polls in the county led to the creation of school districts and voting precincts, adding more lines on the map. Among the 22 school districts depicted on the 1873 Map of Marin County, were these now-defunct districts: San Quentin, Halleck, Bay, Estero, Aurora, Garcia, and Richardson among others. Voters often cast their ballots in the local schoolhouse, although the voting precinct had different boundaries that the school district.

Then there was the matter of tidelands. The Mexican land grants and the confirmed American ranchos did not include tidal marshes and navigable waterways. For instance, Rancho Punta de Quentin included the San Quentin Peninsula and the lower Ross Valley, but it did not include Corte Madera Creek or the vast marshes that surrounded the creek. It had long been shown that shallow waters could be filled with rock and dirt, thus making more land to build upon, and these unclaimed marshlands were sectionalized after California became a state. In the early 1870s the state began a process of surveying tidelands in Marin, producing detailed maps of the potential fill areas, even including, in some cases, streets stretching out into the bay. These tidelands were surveyed and mapped using the sectional system, with township and range, and then put on the market at bargain rates.

This detail of State Tidelands Map No. 7 shows how the sections system was used in surveying marshlands that weren’t part of the rancho claims. This large marsh area is located east of Larkspur and Corte Madera and south of Greenbrae. Much of these wetlands have been filled and developed. Notice the “Public Land” at lower left — the unclaimed land noted above. Anne T. Kent California Room Collection.

Most of the tidelands on the eastern shores of Marin were eventually filled, reshaped, and developed. Look at the recent map of areas that will be affected by sea level rise and you will see the echoes of these surveyed tidelands, designated exactly 150 years ago.

These old land divisions, although seeming archaic in some instances to the modern resident, are still pertinent. Look at a USGS topographic map, or check the deed to your property, and see that the rancho name is how the land is initially identified. See if your house was built on former tidelands. Townships in Marin County are rarely referenced these days except in history books and articles.

Drawing lines across the map of Marin provided order to the patterns of population and settlement, but were an anathema to the Indigenous people who lived on these lands. The mapping and dividing of land marked the end of most traditional Indigenous practices in this rich landscape, both practical and spiritual. Today, the proclamation by roadside signs of watershed boundaries (for instance, “Entering the Lagunitas Creek Watershed”) is one way to reclaim a more holistic view of the land around us.