In 1803, Thomas Jefferson hired ________________________ to explore the land west of the Mississippi River.

______________________ was an American Indian who helped Lewis and Clark understand the language of the American Indians they met.

Because of Lewis and Clark, many people traveled to the West and set up new ______________________.

____________________ were built by people to let boats get through safely.

A ____________________ is a town or city that has a place for ships to land.

A ____________________ is a group of covered wagons that travels together for safety.

The ____________________ helped connect the Great Lakes to New York City.

The __________________ was built to make traveling west easier.

Why was wagon trains so dangerous?

What was the fastest way to travel across the country in 1869?

___________________ are trains that run with steam engines.

_____________________ means "across the continent".

A ___________________ is money that is paid for using a road.

In the early 1900s, transportation ______________________ to improve.

The ____________________ began building airplanes.

The Wright Brothers kept improving their ____________________.