The preferred route
L-1
L-1 is the preferred route wherever it is open: a substantial company abroad that is affiliated with your US company sends someone who worked there full time for at least one continuous year within the three years before the application, in a managerial role or with specialized knowledge.
For a new office in the USA, business premises must be secured, and the first approval is valid for one year at most.
Without a company abroad
E-2
If there is no such company, E-2 may be an option. It requires citizenship of a treaty country (most European countries, including Norway, Sweden, Denmark, Finland, the UK, Ireland and the Netherlands, are on the US State Department's treaty country list), a substantial investment in a real US business that you build and run, and that citizens of the treaty country hold at least half of it.
More on the E-2 investor visa