Due north.
Departing Texas you would travel north to reach South Dakota.
North, maybe northwest.
North
the direction is north.
South Dakota is north of Texas.
Travel north.
Montana, South Dakota, Idaho, Texas
You would travel due north.
15° West of true North.
Yes. From the Canadian border to Mexico through the center of the United States you have: North Dakota, South Dakota, Nebraska, Kansas, Oklahoma, and Texas with Texas being Southernmost and North Dakota being Northernmost.
The direction Texas from Maine is southwest