Some of our troops are there near Manbij, which seems to be about 20-30 miles from the border, not right on it.
http://www.hurriyetdailynews.com/questions-linger-on-who-controls-syrian-town-of-manbij.aspx?pageID=238&nID=110494&NewsCatID=352 (picture)
http://www.al-monitor.com/pulse/originals/2017/03/turkey-misstep-manbij-syria-template-raqqa-erdogan-iraq.html#ixzz4aYpnuSjg
http://www.rudaw.net/english/kurdistan/060320173