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See the comments to the OP question for some important points on other factors that influence growth (spacing, drainage, etc.)

Some plants listed are below the 15 foot limit but might grow that high depending on who you ask, and the conditions.

See the comments to the OP question for some important points on other factors that influence growth (spacing, drainage, etc.). Also pay attention to whether any of the species are invasive in your area. Holly for example is probably invasive on the US west coast.

Some plants listed are below the 15 foot limit but might grow that high depending on who you ask, and the conditions.

There is an almost limitless amount of cultivars for some of these plants. Even after 20 hours of research I was finding new ones. If there's a plant that almost meets your needs in one dimension, try seeing if it has a cultivar that may help in the other dimension.

Note that I am an amateur and have no plant experience. However, based on my research, these plants are evergreen, narrow, and would grow in USDA zone 6b.

See the comments to the OP question for some important points on other factors that influence growth (spacing, drainage, etc.)

For the height and width, I generally took the most conservative estimate for mature height/width I could find. For sun, I went with consensus, but it seems there is some debate. It also does not appear to be consistent what happens when a plant gets less sun than it's supposed to - some die, others grow more slowly, others change color.

Some plants listed are below the 15 foot limit but might grow that high depending on who you ask, and the conditions.

Larger plants may be able to be trimmed to meet these specifications. However, it seems that the less the plant meets the height/width you're going for, the more trimming you will need to do. And trimming can kill or hinder a plant, depending on how receptive it is to trimming.

Finally, it appears that some plants have little to no upper limit on height (or width?). See for example this alleged Juniperus virginiana var. virginiana 'Canaertii' that is easily 50 feet tall and decades(?) old.

Further reading

https://www.thetreecenter.com/eastern-red-cedar-the-toughest-juniper-there-is/

https://leafyplace.com/narrow-evergreen-trees/

Note that I am an amateur and have no plant experience. However, based on my research, these plants are evergreen, narrow, and would grow in USDA zone 6b.

See the comments to the OP question for some important points on other factors that influence growth (spacing, drainage, etc.)

For the height and width, I generally took the most conservative estimate for mature height/width I could find. For sun, I went with consensus, but it seems there is some debate. It also does not appear to be consistent what happens when a plant gets less sun than it's supposed to - some die, others grow more slowly, others change color.

Some plants listed are below the 15 foot limit but might grow that high depending on who you ask, and the conditions.

Larger plants may be able to be trimmed to meet these specifications. However, it seems that the less the plant meets the height/width you're going for, the more trimming you will need to do. And trimming can kill or hinder a plant, depending on how receptive it is to trimming.

Finally, it appears that some plants have little to no upper limit on height (or width?). See for example this alleged Juniperus virginiana var. virginiana 'Canaertii' that is easily 50 feet tall and decades(?) old.

Further reading

https://www.thetreecenter.com/eastern-red-cedar-the-toughest-juniper-there-is/

https://leafyplace.com/narrow-evergreen-trees/

Note that I am an amateur and have no plant experience. However, based on my research, these plants are evergreen, narrow, and would grow in USDA zone 6b.

See the comments to the OP question for some important points on other factors that influence growth (spacing, drainage, etc.)

For the height and width, I generally took the most conservative estimate for mature height/width I could find. For sun, I went with consensus, but it seems there is some debate. It also does not appear to be consistent what happens when a plant gets lets sun than it's supposed to - some die, others grow more slowly, others change color.

Some plants listed are below the 15 foot limit but might grow that high depending on who you ask, and the conditions.

Larger plants may be able to be trimmed to meet these specifications. However, it seems that the less the plant meets the height/width you're going for, the more trimming you will need to do. And trimming can kill or hinder a plant, depending on how receptive it is to trimming.

Finally, it appears that some plants have little to no upper limit on height (or width?). See for example this alleged Juniperus virginiana var. virginiana 'Canaertii' that is easily 50 feet tall and decades(?) old.

Further reading

https://www.thetreecenter.com/eastern-red-cedar-the-toughest-juniper-there-is/

https://leafyplace.com/narrow-evergreen-trees/

Note that I am an amateur and have no plant experience. However, based on my research, these plants are evergreen, narrow, and would grow in USDA zone 6b.

See the comments to the OP question for some important points on other factors that influence growth (spacing, drainage, etc.)

For the height and width, I generally took the most conservative estimate for mature height/width I could find. For sun, I went with consensus, but it seems there is some debate. It also does not appear to be consistent what happens when a plant gets less sun than it's supposed to - some die, others grow more slowly, others change color.

Some plants listed are below the 15 foot limit but might grow that high depending on who you ask, and the conditions.

Larger plants may be able to be trimmed to meet these specifications. However, it seems that the less the plant meets the height/width you're going for, the more trimming you will need to do. And trimming can kill or hinder a plant, depending on how receptive it is to trimming.

Finally, it appears that some plants have little to no upper limit on height (or width?). See for example this alleged Juniperus virginiana var. virginiana 'Canaertii' that is easily 50 feet tall and decades(?) old.

Further reading

https://www.thetreecenter.com/eastern-red-cedar-the-toughest-juniper-there-is/

https://leafyplace.com/narrow-evergreen-trees/