The following is a list of the arterial thoroughfares in Toronto. The city is organized in a grid pattern dating back to the plan laid out by Augustus Jones between 1793 and 1797. Most major roads are aligned in the north-south or east-west direction, based on the shoreline of Lake Ontario. In other words, major north–south roads are generally perpendicular to the Lake Ontario shoreline and major east–west roads are generally parallel to the lake's shoreline. The Toronto road system is also influenced by its topography as some roads are aligned with the old Lake Iroquois shoreline, or the deep valleys. Major roads, which do not conform to the grid pattern and minor streets with documented history or etymology, are listed below.