October Term 2021 · Docket 143 ORIG.

Does groundwater crossing state lines belong to the state it passes through?

Mississippi claims Tennessee pumps water that belongs to Mississippi. Tennessee argues the water is shared and lawfully used.

Official caption
Mississippi v. Tennessee
Latest argument session
Latest official Court activity
Latest verified event
Argued
Sources analyzed through
Official Transcript

Verified source milestones

  1. — An official oral-argument transcript was verified.
  2. — An official oral-argument transcript was verified.

The arguments, in order

This case may have been argued more than once. Each entry below uses that session's official transcript. Later arguments do not erase earlier ones.

  1. Argument 1 ·

    What happened at the argument

    Mr. Coghlan argued equitable apportionment is the wrong remedy for Mississippi.

    Mr. Frederick stated Tennessee has lawfully pumped groundwater for over 130 years.

    Mr. Liu argued no jurisdiction allocates groundwater based on transit through territory.

    Justice Thomas asked if Tennessee could make the same argument against Mississippi.

    Read the official transcript for this argument · Official argument details

    Sources used for this argument breakdown

A citizen's guide to the whole case

What this case is about

Mississippi seeks a court order to stop Tennessee from pumping groundwater. Tennessee wants the case dismissed and its pumping protected.

Official sources for this section

How the case got here

The Supreme Court heard oral argument in this case on October 4, 2021.

Official sources for this section

What each side wants

Mississippi wants a court order to stop Tennessee from pumping groundwater.

Tennessee wants the case dismissed and its pumping protected.

Official sources for this section

What each side says

Mississippi argues groundwater belongs to the state it passes through.

Tennessee argues the aquifer is shared and pumping is lawful.

Official sources for this section

What the justices asked

Justice Kagan asked if Mississippi wins even if the water is interstate.

Chief Justice Roberts asked what other cases involve equitable apportionment besides water.

Official sources for this section

Why it matters

The outcome defines how states share underground water resources. It determines whether one state can claim ownership based on transit. It affects future disputes over shared aquifers.

Official sources for this section

What happens next

This article currently covers the argument record. Use the official docket link for later case activity.

Official sources for this section

Official Court provenance

Official docket and case history · Official Supreme Court oral-argument detail page

Title and summary sources

Revision history

  1. Revision 1 · Official Transcript ·

    Correction: Rewritten to the concise citizen-facing editorial standard.

  2. Revision 2 · Official Transcript ·

    Correction: Migrated to the dated official Court activity contract without model use.

Download this sanitized case as JSON