Nagaoka-kyo was located on a hill south-west of Kyoto valley.
There are several big rivers such as Katsura river, Uji river, Kizu river and Yodo river surrounding the site.
There are also river ports such as Yamazaki tsu and Yodo tsu.
The area was very convenient for travel by both water and road.
In order to build Nagaoka-kyo, they excavated the hill and reclaimed the valley and lowland with the earth from that excavation.
The city was designed on flat land as a model for the Heijo-kyo.
Suzaku Ooji as a main street and Nagaoka-gu on the north edge housing the Imperial palace and government offices.
Nagaoka-gu has Ichijo Ooji (or Kita Kyogoku Ooji) to the north and Nijo Oojito the south. From East to west is about 1km, and from south-north about 1.6km.
The whole area is surrounded by Ryouichibou Ooji.
In Nagaoka-gu there is accommodation for two governors and 8 ministries for example Naidai-Choudouin.
The east part of Suzaku Ouji is called Sakyo and the west part called Ukyo.
This is a large area of about east-west 4.3km, south-north 5.3km
It was divided by a grid called 'Jobou sei' on the basis of a 1800 syaku (533 meter) square.
Each part is called a Bou (street word) .
The border of a Bou is divided from Kita Kyougoku to Kujo (east-west direction), both Sakyo and Ukyo (south-north directions) from Ichiou to Shibou which is a wide road.
Each Bou is divided still more into 16 towns occupying areas of 120 meter.
Each town has a number.
Nagaoka-kyo's graphic line is very straight (both east-west and south-north) and the width of road is from 15 to 24 meters.
It is easy to imagine how big the city plan was at that time.