In the United States, the choice of cities to achieve a high return on investment (ROI) for your advertising efforts can be influenced by several factors. Here are some cities that are known for their economic opportunities and diverse markets, but it’s essential to evaluate them in the context of your specific business and goals:

1. New York City, New York: As the largest city in the U.S., New York City offers access to a vast and diverse customer base. It’s a hub for numerous industries and has a thriving business ecosystem. However, advertising costs can be high due to the level of competition.
2. Los Angeles, California: Los Angeles is another major metropolitan area with a diverse population. It’s especially attractive for businesses in the entertainment, fashion, and technology sectors.
3. San Francisco, California: The San Francisco Bay Area, including Silicon Valley, is a tech and innovation hub. It’s ideal for businesses in the technology and startup space.
4. Chicago, Illinois: Chicago is a major economic and transportation center in the Midwest. It’s a great choice for businesses seeking to target the Midwest region.
5. Houston, Texas: Houston has a robust economy, particularly in energy, healthcare, and aerospace. It’s an excellent choice for businesses operating in these sectors.
6. Dallas, Texas: Dallas is a thriving business hub with a diverse economy. It’s especially attractive for businesses in finance, telecommunications, and healthcare.
7. Atlanta, Georgia: Atlanta is a growing city with a strong economy and a favorable business environment. It’s ideal for businesses looking to tap into the southeastern U.S. market.
8. Miami, Florida: Miami serves as a gateway to Latin America and has a vibrant multicultural population. It’s a good choice for businesses with an international focus.
9. Seattle, Washington: Seattle is a technology and innovation hub, home to major tech companies like Amazon and Microsoft. It’s a great location for tech-focused businesses.
10. Boston, Massachusetts: Boston is known for its thriving education and healthcare sectors. It’s ideal for businesses in these industries.
11. Denver, Colorado: Denver’s economy has been on the rise, attracting professionals and businesses. It’s suitable for a variety of industries, including tech, healthcare, and outdoor recreation.
12. Austin, Texas: Austin is known for its tech scene and a growing startup ecosystem. It’s a great choice for technology-related businesses.

Remember that while these cities offer opportunities for high ROI, your success will depend on factors like your target audience, competition, and the specific industry you operate in. Thorough market research and a well-planned advertising strategy are essential for maximizing your ROI in any city.