After the purchase of the Louisiana territory, Thomas Jefferson wanted people to find the North passage and map a westward route. He assigned Meriwether Lewis and William Clark to mount an expedition to do so. Accompanying them would be York, a slave that worked for Clark. Along their journey they met Sacagawea and guided them through her territory. They made it to their destination, the Pacific ocean. They didn't complete their initial goal, but they made relations with Indians, and mapped a westward route to the pacific ocean.
Some tools and items they took along with them are clothing, syringes, sewing needles, firearms for protection, ammo to load the firearms, steels for fire, a surveyor compass for measuring areas and whetstones to sharpen their tools if needed.
They had to overcome significant challenges to complete the expedition. They had to go through the rough and intense currents rowing up the Missouri River, leaving them very blistered, sore and fatigued. When they were on land and set up camps, they were sometimes followed up with bear attacks. When they climbed the rockies, they were faced with almost no food and stricken with starvation.
During their travels, they had discovered some plant and animal species. For example, Harbor seals, which can be found by arctic coastlines. They also found Prickly Pear Cactuses, they are common in the Indian Fig. Also, they found a Black tailed Prairie dog, they are found in the Great Plains.
The route that Lewis and Clark had taken stretched for miles upon miles and many more. The first part of the route is when they left their town of Saint Louis, and traveling by boat through Missouri's intense currents. They travel through unknown Indian territory in the summer. By winter, they camped in North Dakota by a nearby Mandan village. After that they went through the rough terrain of the rocky mountains, thanks to sacagawea, she persuaded her people to give them horses to cross with. They then reach their final destination, the Pacific ocean.
They may not have accomplished their original goal, to find the North Passage, but it doesn't exist in the first place. They have accomplished other goals. They had traveled over eight-thousand miles of territories overcoming every obstacle. They had made good relations with many many Indian tribes and villages, to allow for communication. Without their help, they would not have gone to where they did. Finally, after all their troubles, they had found mapped an entire west route directly to the Pacific ocean.