One of the distinctions that Portland generally has is a very fine grained series of streets, and the streets themselves create perfectly sized square city blocks. Now this might not come to be a surprise and Portland is certainly not the only city with such consistent square city block pattern. New York City, Salt Lake City, and even Toronto and Hamilton has a series of grid block pattern, but in Portland these perfectly square city blocks cover a large area of the city. A simple search of Portland Oregon will reveal a city of what I am talking about (see below). The map below shows how consistent the blocks are, and other than the Interstate highway, the Willamette River, and various open spaces, the pattern is pretty much intact as it was created when the city was founded. Other than the South and North Park Blocks and land around rough terrain, each city block measures 200 feet by 200 feet which is smaller than New York City’s grid, and represents one of the smallest and fine grained city blocks in the US. Carson City's grid blocks are even smaller at 180 feet by 180 feet [Link].
When walking on the streets, one does not immediately capture the importance of having such fine grained city blocks until you have to walk an extra distance to get to your destination because there was not a shorter, more direct route. The ability to go from origin to destination in the shortest route is possible when the street connectivity is high. And with each block no more than 200 feet in length, Portland represents one of the most connected cities you can find. But how did Portland's famed grid streets come to be?
History:
Portland was founded in 1845 and was incorporated as a city in 1851 where the population was 800 [Link] where it eventually grew quickly due to the forest industry and its importance of the city due to its location on the Columbia River. By 1879 it had a population of 17,500 inhabitants. The street grid you see today was planned in 1845 by Thomas Brown [Link] for a 16 block stretch of land on both sides of the Willamette River (a major tributary of the Columbia River). As the city grew, the city blocks continued to expand in the same 200 feet by 200 feet configuration. Due to the configuration of the Willamette River, the grid pattern shifted so the east-west streets more or less remain in perpendicular with the river. This signifies the importance of the Willamette River in the development of the city.
As the city continued to grow eastward the street network basically stayed the same. It was only when city growth hit the West Hills in the west end of the city was it impossible to impose the grid pattern, and development grew in favour of a more organic network of streets. The illustration below is from The Greater Portland Plan by Edward H. Bennett which was a master plan document released in October 1912, and shows what Portland would have been like in 1881. This would have been taken from the West Hills looking down to Portland in the foreground, the Willamette River in the middle, and the Industrial Eastside in the background with the Cascade Ranges in the far background.
There are theories as to why the street network was designed the way they did. One theory is the blocks maximize the use of land. Remember in those days, you did not have massive 30-storey commercial buildings that can take up a large building footprint. Rather, you would have smaller buildings to meet the needs of a small but growing city. The second theory is the opportunity to maximize the number of corner lots, which would afford a higher land value due to the presence of two streets fronting on a lot. That also affords higher revenues generated by commercial establishments due to twice the number of pedestrians as opposed to a corner lot.
Legacy:
The foresight into the developing the city through the expansion of the original 16 blocks of perfectly laid squares has left a legacy as a city that embraces walkability. The city center is a compact community of medium and high density commercial and residential development. Due to the small size of the city blocks, development is restricted to just the block itself, limiting the size of these buildings and the ability to create intense development and still provide parking on-site. This makes the city center less claustrophobic and more inviting, and building heights that are not excessive. The only exception to this is the US Bancorp Tower, the second tallest building in the city, where it takes up the equivalent of two city blocks, but luckily this is a one-off situation and is not the norm.
The grid street pattern throughout the city also allows for efficient laying of public transit routes such as TriMet's MAX LRT trains, dozens of bus routes, and the Portland Streetcar. Because most of the these streets are one-way streets, the transit routes fan out and spread out to provide further transit coverage throughout the city. In fact, if it wasn't for the existing street network, it might be difficult to spread transit the way it does today, and transit vehicles would either have to run through opposing traffic, force one-way streets to become two-way streets, or to separate the transit routes so far apart it becomes infeasible as transit routes would have to run several blocks from each other.
The next time you visit Portland, have a look at the street pattern, and you will see how the grid pattern has contributed to such a vibrant city center and makes the city such a walkable city.
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