Does emus only live in Australia because there was one spotted in Charles County?

Emus are native to Australia, but no longer endemic to that country. Because emu farming has taken place in other countries around the world, such as USA and even India, circumstances have resulted in emus being left to fend for themselves in the wild. The emu is quite an adaptable bird, and has readily taken to new environements, so it is certainly possible these days to see wild emus in other countries.